A predator–prey model with disease in the predator species only

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HOPF BIFURCATION OF AN INFECTED PREDATOR-PREY SYSTEM WITH PREY REFUGE

Xia LLeabharlann iu ‡(C o ll ege o f Ma th . a nd Info rma tio n Sc ie nce, H ena n N o rma l Un iv ersity , X inxia ng 4 5 30 0 7, He na n )
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In t his pap er, a n infect ed pre dat or-prey mo del with prey refug e is invest iga ted . T he eﬀect s o f refug e on t he st ab ilit y o f t he equilibria o f the syst em a re a na lyzed. Mo reover, using the crite rion int ro duc ed by L iu, w e derive t he H o pf bifurca t io n co ndition s o f t he syst em w it h re sp ect t o the refug e va lu e. Key wor ds infe cted prey; H opf bifurcat io n; pre y refug e; st ability 20 00 M athem atic s Sub ject C lassiﬁc ation 3 4 C2 5; 9 2B 05
1
Introduction
Rec en tly, man y rese arche s h ave paid on the eﬀe ct of prey refu ge on th e dyn amics of the pre dator-p rey system [1- 5]. As G on z´ a lez -O livares [1] an d Che n [2] pointe d ou t th at the pre y re fuge has stron g im pac t on th e instab ility and stab ility prop erties of equ ilib ria and the un ique ne ss an d existen ce of lim it cyc le of the syste m was stud ie d. H uan g, Ch en an d Li [3] in vestigated a p red ator- pre y m ode l with Holling typ e III fun ction al resp onse inc orp oratin g a p re y re fuge , an d pointe d out th at inc reasing th e amou nt of p rey refu ge cou ld inc rease the p rey de nsities and lead to p opu lation ou tbre aks. Won ly ul an d K imun [4] stu died a pre dator-p rey mo de l with H ollin g typ e II fun ctional resp onse in corp oratin g a prey re fuge . Un de r homoge ne ous N eu man n b ou nd ary con dition, the y d isc usse d th e asym ptotic b eh avior of sp ec ially in hom ogen eou s solu tions an d the local e xisten ce of p eriod ic solu tion s. On th e othe r h and , n ume rous stud ie s h ave also shown th e im p ortan ce of transmissible disease in regulating ec ological situ ation . For exam ple, Han an d M a [6] in vestigate d the pre dator-p rey systems for SIS and S IR d ise ases w ith th e stan dard and m ass action incide nc es. Ven turino [7] ex amine d e pide mic m ode ls in pre dator-p rey mod els with d ise ase in the p red ators. Packer et al [8] analyze d th e im plications of pre dator control for infe ctious disease an d sugge ste d that if th e prey h as an in fec tiou s d isease, the n the p red ator rem oval m ay le ad to a de crease d p rey p opu lation siz e. K rishn a pad a D as, Sh ovon lal an d Ch attopad hyaya

2024-2025学年度高一英语下学期期末考试卷(含答案)

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1. What does the man say about Jack?A. He's humorous.B. He's responsible.C. He's serious.2. What is the probable relationship between the speakers?A. Cousins.B. Classmates.C. Uncle and niece.3. What are the speakers mainly talking about?A. What to have for lunch.B. Where to buy some vegetables.C. Who will cook a meal.4. Where are probably the speakers?A. In the car shop.B. In the toy shop.C. In the clothing shop.5. What does the man usually do in his spare time?A. Play chess with his grandfather.B. Play video games.C. Do some exercise.第二节 (共15小题; 每题1.5分, 满分22.5分)听下面5段对话或独白。

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EXISTENCE AND GLOBAL ATTRACTIVITY OF PERIODIC SOLUTIONS TO A PREDATOR-PREY SYSTEM WITH DELAYS AN

1
Introduction
In [1], May introd u ced th e following p red ator-pre y sy ste m � h dH ( t ) H (t − τ ( t)) i � � = r H (t ) 1 − − αH (t ) P ( t) , dt K � � dP ( t ) = − bP ( t) + β P ( t ) H ( t − σ ( t )) , dt
An n. of D iﬀ. Eqs . 24:2(2008) , 197-207
EXISTENCE AND GLOBAL ATTRACTIVITY OF PERIODIC SOLUTIONS TO A PREDATOR-PREY SYSTEM WITH DELAYS AND IMPULSES ∗ †
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B y usin g Ga ines an d M aw hin ’s c ont inua tio n t heo rem of co incidence deg ree theo ry a nd co nstruct ing L yapu nov funct io na ls, a se t o f ea sily veriﬁable suﬃ cient co nditio ns a re derived for t he exist ence a nd g lo ba l a t trac tivity o f a po sitive perio dic so lut io n t o a predat o r-prey syst em with dela ys a nd impu lses. Key wo rds perio dic so lut ion; im pulsive e qu at io n; c oincidence deg ree t heo ry; globa l a t trac tivity 20 00 M athem atic s Sub jec t C lassiﬁc ation 3 4 K13 ; 92 D2 5

2025届浙江“七彩阳光”新英语高三上期末学业水平测试模拟试题含解析

2025届浙江“七彩阳光”新英语高三上期末学业水平测试模拟试题注意事项:1．答题前，考生先将自己的姓名、准考证号码填写清楚，将条形码准确粘贴在条形码区域内。

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第一部分（共20小题，每小题1.5分，满分30分）1．Tom’s sco re on the test is the highest in the class. He _____.A．should study last nightB．should have studied last nightC．must have studied last nightD．must study last night2．The Chinese people are kind and caring. If not, I _____ in China in the past 30 years. A．didn’t stay B．hadn’t stayedC．couldn’t stay D．couldn’t have stayed3．If you ___________ to my advice carefully, you wouldn’t have made such a terrible mistake.A．listened B．have listenedC．would listen D．had listened4．She is stubborn in resisting his enquiries about the Moonstone _____ the degree that she makes it seem as if she does not want the mystery ______.A．on; to solve B．with; solvingC．for; being solved D．to; to be solved5．Thanks to her determination and perseverance on the piano lesson, she has a ______ grasp of the subject.A．comprehensive B．confidentialC．conservative D．compulsory6．---Professor Li is wanted on the phone. Where is he?--- I saw him coming, but in a minute, he _____.A．will disappear B．has disappeared C．disappears D．disappeared7．There is no easy way to remember prepositions, as it is one area of English____ the rules seem very irregular.A．that B．whereC．whose D．which8．—The battery in my cell phone is running low.—I that last night before we went to bed.A．was noticing B．have noticed C．would notice D．had noticed9．Was it at the beginning _____ you made the promise ____ you would do all to help make it?A．that; that B．when; thatC．that; when D．when; when10．I would persuade her to make room for you ______it be necessary.A．could B．mightC．should D．would11．You can only be sure of _____ you have at present; you cannot be sure of something _____ you might get in the future.A．that; what B．what; / C．which; that D．/; that12．Could I speak to__________ is in charge of International Sales please?A．who B．whatC．whoever D．whatever13．______in painting, John didn’t notice evening approaching.A．To absorb B．To be absorbedC．Absorbed D．Absorbing14．—________! Somebody has left the lab door open.—Don’t look at me.A．Hi, there B．Dear meC．Thank goodness D．Come on15．At the meeting they discussed three different ________ to the study of mathematics. A．approaches B．meansC．methods D．ways16．________ your generous help, I do believe I have a better understanding of your country and culture.A．But for B．Out ofC．Thanks to D．As to17．The economy in big cities has continued to rise thanks to the local governments to increase ______.A．that B．themC．it D．those18．If you are feeling so tired, perhaps a little sleep would____．A．act B．helpC．serve D．last19．--- Did you watch the final match of China Open yesterday?---Sure. I it so attentively that I forgot to cook supper.A．watched B．had watchedC．was watching D．was to watch20．Children exposed to air pollution are more to suffering from different diseases.A．possible B．probable C．likely D．certainly第二部分阅读理解（满分40分）阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。

MULTIPLE PERIODIC SOLUTIONS TO A MICHAELIS-MENTEN-TYPE PREDATOR-PREY SYSTEM WITH DELAY AND HARVE

M U LT IP LE P E R IO DI C SO LUT ION S T O A M I CH A E LIS-M E N T E N -T Y P E P R E DAT O R -P R E Y SYST E M W IT H D E LAY AN D H A RV ES T IN GWangsheng Xie,P eixuan Weng(School of Ma th.,South China Norm a l Unive r sity,Gua ngzhou 510631)Ann.of Di .Eqs.28:3(2012),352-357A bs t r a ctIn t his pa per ,t he existen ce of eight p eriodic solut ions t o a Michaelis-M enten -type pr eda tor-p rey system with delay a nd h ar vest ing in p at ch environm ent is esta blished using t he a nalytica l t echniqu es a nd M awhin ’s coincidence de gr ee t heor y.K e y wor d s M icha elis-Ment en-type pr eda tor -prey syst em;delay;ha r vesting;mu l-t iple per iod ic solut ions2000M a t h e m a t ic s S u b je ct C la ssi c a t ion 34K13;92D251I nt r od u ct ionIn t his paper,we consider t he following predat or-prey syst em with Michaelis-Ment en type funct ional response and harvest ing t erms in t wo patches:˙x 1(t)=x 1(t)[b 1(t )a 1(t)x 1(t )k 1(t)y(t )c(t )y(t)+x 1(t )]+D 1(t)(x 2(t )x 1(t))h 1(t ),˙x 2(t)=x 2(t)[b 2(t )a 2(t)x 2(t )]+D 2(t )(x 1(t)x 2(t ))h 2(t),˙y(t)=y(t)[r (t)a 3(t )y(t)+k 2(t )x 1(t τ)c(t)y(t τ)+x 1(t τ)]h 3(t),(1.1)where x i (t )denot es t he densit ies of prey in i t h patch at t ime t ,and y(t)denotes t he densityof predat or of t he 1-st pat ch at t ime t ;h j (t)(j =1,2,3)are the harvest ing t erms;b i (t ),a i (t ),D i (t ),k(t ),c(t ),h j (t),r(t ),i =1,2,j =1,2,3,are cont inuous,bounded and st rict ly posit ive ω-periodic funct ions,and ω>0is a const ant.Here,we assume t hat t he rst pat ch has predat or and prey species,and t he second pat ch has only prey species,and t here is a di usion of prey individuals bet ween t he t w o pat ches.For t he corresponding backgrounds,please see [1,3-9].The main aim of t his art icle is to show t hat (1.1)has eight posit ive ω-periodic solut ions.The remaining of t his paper is organized as follows.In Sect ion 2,we present our main result.The t echniques used in t his article is Mawhin ’s cont inuat ion t heorem combining wit h some analyt ic skills.2E x ist en ce of M u lt ip le P o sit ive P er io d ic So lu t io n sLet X and Z be real Banach spaces,L :DomL X →Z be a linear cont inuous mapping,and N :X →Z be a cont inuous mapping.If L is a Fredholm m apping of index zero,t hereM anuscr ipt r eceived J a nuar y 27,2012;R evised Apr il 10,2012C orr espon ding a uth or.E -ma il:wengpx@352No.3W.S.Xie,etc.,PERIODIC SOLUT IONS T O PR EDAT OR-P REY SYS.353exist cont inuous projectors P:X→X and Q:Z→Z such t hat ImP=KerL,ImL= KerQ=Im(I Q)and X=KerL⊕KerP,Z=ImL⊕Im Q.If we de ne L p=L|D om L∩K erP, t hen L p is invertible,and let K p=L1p.Assume t hat is a bounded open set in X.If QN()and K p(I Q)N()are relat ively compact set s in Z and X respectively,t hen we call N is L-compact on.Because Im Q is isomorphic t o KerL,t here exist s an isom orphism J:Im Q→KerL.In t his section,we shall prove t he exist ence ofω-periodic solutions using Mawhin’s continuat ion t heorem list ed in t he following.Lem m a 2.1[2]L et L be a Fredholm mapping of index zero and N be L-compact on ×[0,1].Suppose that:(a)Lx=λN(x,λ),for anyλ∈(0,1),x∈∩Dom L;(b)QN(x,0)=0,for any x∈∩KerL;(c)deg{J QN(,0),∩KerL,0}=0.Then Lx=N(x,1)has at least one solut ion in∩DomL.Assuming that f is a cont inuousω-periodic funct ion de ned in R,we denot ef=1ω∫ωf(t)dt,f M=maxt∈[0,ω]f(t),f L=mint∈[0,ω]f(t).First ly,we give t he following assumpt ions:(A1)h L1>D M1R;(A2)h L2>D M2R;(A3)b L1(k1/c)M D M1>2√a M1h M1;(A4)b L2D M2>2√a M2h M2;(A5)B r M>2√a M3h M3,whereR:=max {(b1h1)M,(b2h2)M},B:=k L2c M(k2a3)M11+1.For convenience,we also int roduce some posit ive numbers as follows:±1:=b M1±√(b M1)24a L1(h L1D M1R)2a L1,H±1:=[b L1(k1c)MD M1]±√[b L1(k1c)MD M1]24a M1h M12a M1,±2:=b M2±√(b M2)24a L2(h L2D M2R)2a L2,H±2:=(b L2D M2)±√(b L2D M2)24a M2h M22a M2,±3:=(k M2r L)±√(k M2r L)24a L3h L32a L3,H±3:=(B r M)±√(B r M)24a M3h M32a M3.By(A1)-(A5),we can show t hat1<H1<H+1<+1,2<H2<H+2<+2,3<H3<H+3<+3.(2.1) Now we can present our main result.T heor em 2.1Assume tha t(A1)-(A5)hold,then system(1.1)has at least eight posit ive ω-periodic solut ions.354ANN.OF DIFF.EQS.Vol.28P r oof By m aking t he change of variables x 1(t )=e v 1(t ),x 2(t)=e v 2(t ),y(t )=e v 3(t ),syst em (1.1)can be reformulat ed as ˙v 1(t)=b 1(t )a 1(t)ev 1(t )k 1(t )e v 3(t )v 3(t )v 1(t )+D 1(t )(e v 2(t )v 1(t )1)h 1(t )e v 1(t )=:f 1(v,t ,λ),˙v 2(t)=b 2(t )a 2(t)e v 2(t )+D 2(t )(e v 1(t )v 2(t )1)h 2(t )e v 2(t )=:f 2(v,t ,λ),˙v 3(t)=r (t)a 3(t )ev 3(t )6+k 2(t )e v 1(tτ)c(t)e v 3(tτ)+e v 1(tτ)h 3(t )e v 3(t )=:f 3(v,t ,λ).(2.2)De ne two spacesX =Z ={v =(v 1,v 2,v 3)T ∈C (R,R 3):v i (t +ω)=v i (t),i =1,2,3}wit h t he norm ∥v ∥=∥v ∥X =∥v ∥Z =3∑i =1max t ∈[0,ω]|v i (t)|.Then bot h X and Z are Banachspaces.LetL :Dom L →Z,Lv =v ′,DomL ={v ∈X :v ∈C (R ,R 3)}X,N :X ×[0,1]→Z,N (v,λ):=(f 1(v,t ,λ),f 2(v,t,λ),f 3(v,t,λ))T .Obviously,ImL ={v=(v 1,v 2,v 3)T ∈Z :∫ω0v i (t)dt =0,i =1,2,3}is closed in Z ,KerL =R 3,dimKerL =codim Im L = 3.Hence,L is a Fredholm mapping of index zero.De ne P :X →X,Q :Z →Z as follows:v 7→v =1ω∫ω0v(t )dt ,t hen Im P =KerL,ImL =KerQ =Im(I Q).The generalized inverse (t o L)is K p :ImL →DomL ∩KerP which is given by[K p v](t )=∫t 0v(s )ds 1ω∫ω0∫t0v(s )ds dt.Therefore,QN (v,λ)=1ω∫ω0f 1(v,t ,λ)dt 1ω∫ω0f 2(v,t ,λ)dt 1ω∫ωf 3(v,t ,λ)dt ,K p (IQ)N (v,λ)=1(v,t ,λ)2(v,t ,λ)3(v,t ,λ),wherej(v,t ,λ)=∫tf j (v,s,λ)ds1ω∫ω0∫tf j (v,s ,λ)ds dt(t ω12)∫ωof j (v,s ,λ)ds.Obviously,QN and K p (I Q)N are cont inuous,and K p (I Q)N (×[0,1])is compact for anyopen bounded set X using t he Arzela-Ascoli t heorem.Moreover,QN (×[0,1])R 3is bounded.T hen N is L-com pact on ×[0,1].To apply Lemma 2.1,w e need to nd at least eight bounded open set s i (i =1,2,,8),in which t he assum pt ions in Lemm a 2.1are sat is ed.Considering the operat or equat ion with paramet er λ:Lv=λN (v,λ),λ∈(0,1),we have˙v 1(t )=λf 1(v,t,λ),˙v 2(t)=λf 2(v,t ,λ),˙v 3(t )=λf 3(v,t,λ).(2.3)No.3W.S.Xie,etc.,PERIODIC SOLUT IONS T O PR EDAT OR-P REY SYS.355Assume t hat (v 1(t),v 2(t),v 3(t))T is an ω-periodic solut ion t o syst em (2.3)for some λ∈(0,1).Then t here exist t i ,s i ∈[0,ω](i =1,2,3)such t hatv i (t i )=max t ∈[0,ω]v i (t ),v i (s i )=m in t ∈[0,ω]v i (t ),i =1,2,3.It is clear t hat v ′i (t i )=0,v ′i (s i )=0(i =1,2,3).This t oget her wit h (2.3)leads t of j (v(t j ),t j ,λ)=0,f j (v(s j ),s j ,λ)=0,j =1,2,3.(2.4)If v 1(t 1)≥v 2(t 2),t hen v 1(t 1)≥v 2(t 1).This toget her wit h (2.4)leads t ob 1(t 1)h 1(t 1)e v 1(t 1)>0,t hat is,e v 1(t 1)<b 1(t 1)h 1(t 1)≤(b 1h 1)M .Hence,v 2(t 2)≤v 1(t 1)<ln(b 1h 1)M≤ln R.(2.5)If v 1(t 1)<v 2(t 2),t hen v 1(t 2)<v 2(t 2).This toget her wit h (2.4)leads t ob 2(t 2)a 2(t 2)e v 2(t 2)>0,t hat is,e v 2(t 2)<b 2(t 2)a 2(t 2)≤(b 2a 2)M.Hence,we havev 1(t 1)<v 2(t 2)<ln(b 2a 2)M≤ln R.(2.6)By (2.5)and (2.6),we obt ainmax{v 1(t 1),v 2(t 2)}<ln R ,t hat is,b 1(t 1)a 1(t 1)e v 1(t 1)k 1(t 1)c(t 1)D 1(t 1)h 1(t 1)e v 1(t 1)<0,(2.7)t hena M 1e2v 1(t 1)[b L 1(k 1c )MD M 1]e v 1(t 1)+h M 1>0.(2.8)Similarly,we obt ain from (2.4)t hata M 1e 2v 1(s 1)[b L1(k 1c )MD M 1]e v 1(s 1)+h M1>0.(2.9)By (2.4),we haveb 1(t 1)a 1(t 1)ev 1(t 1)+D 1(t 1)e v 2(t 1)v 1(t 1)h 1(t 1)e v 1(t 1)>0,t hen w e obt aina L 1e2v 1(t 1)b M 1e v 1(t 1)+(h L 1D M1R)<0.(2.10)Similarly,we obt ain t hata L 1e2v 1(s 1)b M 1e v 1(s 1)+(h L 1D M1R)<0.(2.11)Not ing (A 1)and (A 3),it follows from (2.8)and (2.10)t hat{v 1(t 1)>ln H +1or v 1(t 1)<ln H 1,ln1<v 1(t 1)<ln+1.356ANN.OF DIFF.EQS.Vol.28Hence,v 1(t 1)∈(ln1,ln H 1)∪(ln H +1,ln+1).(2.12)Similarly,from (2.9)and (2.11),we havev 1(s 1)∈(ln1,ln H 1)∪(ln H +1,ln+1).(2.13)Generally,one can obt ain from (A 1)-(A 5)t hat for j =1,2,3,v j (t j )∈(lnj,ln H j )∪(ln H +j ,ln +j),v j (s j )∈(lnj,ln H j )∪(ln H +j ,ln +j).(2.14)Summarizing t he above discussion,we derive from (2.12)-(2.14)t hatv j (t )∈(lnj,ln H j )∪(ln H +j ,ln +j),j =1,2,3.Obviously,ln ±1,ln ±2,ln ±3,ln H ±1,ln H ±2,ln H ±3are independent of λ.Now,let 1,2:={v=(v 1,v 2,v 3)∈X |v 1(t)∈(ln 1,ln H 1),v 2(t)∈(ln 2,ln H 2),v 3(t)∈(ln 3,ln H 3)},3,4:={v=(v 1,v 2,v 3)∈X |v 1(t)∈(ln 1,ln H 1),v 2(t)∈(ln ±2,ln H ±2),v 3(t)∈(ln 3,ln H 3)},5,6:={v=(v 1,v 2,v 3)∈X |v 1(t)∈(ln 1,ln H 1),v 2(t)∈(ln ±2,ln H ±2),v 3(t)∈(ln +3,ln H +3)},7,8:={v=(v 1,v 2,v 3)∈X |v 1(t)∈(ln +1,ln H +1),v 2(t )∈(ln +2,ln H +2),v 3(t )∈(ln 3,ln H 3)},Then,for every i ∈{1,2,,8},i is a bounded open subset in X.Furt herm ore,we havei ∩j =,i =j ,i,j =1,2,,8.Therefore,each i sat is es (a)of Lemm a 2.1.Now,we show t hat condit ion (b)of Lem ma 2.1holds for each i .That is,for anyv ∈i ∩KerL =i ∩R 3(i =1,2,,8),QN (v,0)=0.If it is not t rue,t hen t here exist s a v =(v 1,v 2,v 3)∈i ∩R 3such t hat QN (v,0)=0.T herefore,we haveb 1a 1e v 1h 1e v 1=0,b 2a 2ev 2h 2e v 2=0,r a 3e v 3+k 2h 3e v 3=0.(2.15)By (A 1)-(A 5),(2.15)has eight dist inct solut ions:1,2=(v 1,v 2,v 3),3,4=(v 1,v ±2,v 3),5,6=(v 1,v ±2,v +3),7,8=(v +1,v +2,v 3),wherev ±1=lnb 1±√b 124a 1h 11,v ±2=lnb 2±√b 224a 2h 22,v ±3=lnk 2r ±√(k 2r)24a 3h 33.Combining wit h (2.1),it is easy to verify t hatlnj<v j <ln H j <ln H +j <v +j <ln +j,j =1,2,3,(2.16)which implies v ∈i ∩R 3.This cont radict s v ∈i ∩R 3.Hence,(b)of Lemma 2.1holds.Next ,we show t hat (c)of Lem ma 2.1holds for each i .It follows from (2.16)t hati ∈i (i =1,2,,8).Since KerL =ImQ,J =I.Assume t hat v is a solut ion to syst em (2.15)in i .Therefore,by com put ing t he J acobi det erm inant of the operat or on t he left of (2.15),we haveNo.3W.S.Xie,etc.,PERIODIC SOLUT IONS T O PR EDAT OR-P REY SYS.357deg{J QN(v,0),i∩KerL,(0,0,0)T}=sign a1e v1+h1e v1000a2e v2+h2e v200a3e v3+h3e v3.From t his and(2.15),we obtain t hat for i=1,2,,8,deg{J QN(v,0),i∩KerL,(0,0,0)T}=sign[(b12a1e v1)(b22a2e v2)(k2r2a3e v3)]. Then,substit ut ing t he eight solut ions to(2.15)into t he above formula,we havedeg{J QN(v,0),i∩KerL,(0,0,0)T}=1,i=1,5,6,7;deg{J QN(v,0),i∩KerL,(0,0,0)T}=1,i=2,3,4,8.Now,we prove t hat each i sat is es all t he assumptions of Lemma2.1,and t hus(2.2)has an ω-periodic solution in i.That is,syst em(2.2)(and t hus(1.1))has at least eightω-periodic solut ions.T he proof of Theorem2.1is complet e.R efer en ces[1]M.A.Aziz-Ala oui,M.Dah er Okiye,B oundeness a nd globa l sta bility for a pred at or-pr ey m odelwith modi ed Leslie-Gower and Holling-t ype I I sc h emes,Appl.M at h.Le tt.,16(2003),1069-1075.[2]R.E.Ga ines,J.L.M awhin,Coincide nce Degr ee a nd Nonlinea r Di er ential E qu at ions,Spr inger-Ver la g,Be rlin,1977.[3]S.B.Hsu,T.W.Hwan g,Y.Ku ang,R ich dyna mics of a r at io-dep endent one-pr ey t wo-pred at or smodel,J.Ma th.B iol.,43(2001),377-396.[4]W.Ko,K.Ryu,Qua lit at ive a nalysis of a pred at or-pr ey model wit h Holling type II func tiona lresponse in cor pora t ing a pre y r efuge,J.Di ere ntial Equations,231(2006),534-550.[5]T.Lindstr om,G loba l st a bilit y of a m odel for comp eting pr eda t or s:An e xt ension of th e Ar dit o&R iccia rdi Lya punov f un ction,Nonlinea r Anal.,39(2000),793-805.[6] A.F.Nindjin,M.A.Az iz-Alaoui,M.C adivel,Analysis of a pr eda tor-prey m odel wit h m odi edLe slie-G owe r a nd Holling-typ e II sche mes wit h t im e delay,Nonlinea r Anal.RWA,7(2006),1104-1118.[7]R.K.Upa dhya y,S.R.K.I yenga r,E ect of sea sona lity on the dynam ics of2an d3speciesprey-p reda t or syst ems,Nonlin e a r Ana l.RWA,6(2005),509-530.[8]Fengying Wei,Existence of m ult iple p osit ive p eriodic solu tions t o a p eriodic preda t or-pr eysystem wit h ha r vest ing t er ms and Holling II I type funct iona l response,C omm un.Nonlinea r Sci.Nume r.Simul.,16(2011),2130-2138.[9]Kaihong Zha o,Yongkun Li,Four posit ive per iod ic solut ions t o t wo sp ecies p ar asitical syst emwith har vest in g t er ms,C omput.Ma th.Appl.,59(2010),2703-2710.(edited by Liangwei Huang)。

译林版高中英语选择性必修第二册Unit3 Fit for life Part 3 练习含答案

Part3Extended reading,Project,Assessment&Further study基础过关练Ⅰ.单词拼写1.(2023江苏常州九校期中联合调研)You can persuade yourself with your choice if you're not careful,and if you do,it'll probably(滥用)your choices.2.(2020新高考Ⅰ)He turned to the forest(部门)for help but was told that nothing would grow there.3.(2021北京)Researchers in many areas have projected the(广泛的)collapse as“a credible scenario(情景)this century”. Ⅱ.一词多义1.A back injury forced her to withdraw from the volleyball game.2.The people in the building withdrew in time from the big fire.3.After his mother died,he began to withdraw into himself.4.The drug was withdrawn from sale due to its false advertising.Ⅲ.单句语法填空1.According to the expert,the vase has a history dating backthe early Tang Dynasty.2.The child's chair was low.The teacher adjusted itthe height where he could see the blackboard.3.There are several theories accounting for these (phenomenon)which are reflected in the picture.4.(2023北京)And I applied with the same(anxiety) excitement as before.5.Afterwards,with more trees cut down,the environment they lived in was(severe)damaged gradually.6.The new labs are with advanced,which motivates us students to study hard to achieve our goals.(equip)7.It is bad manners to laugh at people.Most of us may end up in one day.(disable)8.There is growing evidence staying up late has a serious impact on people's health.9.Now that she is out of work,Lucy(consider)going back to school,but she hasn't decided yet.Ⅳ.完成句子1.花太多的时间在网上是不健康的,并且让人很难集中精力在生活中的其他事情上。

PERMANENCE AND GLOBAL STABILITY OF A DELAYED RATIO-DEPENDENT PREDATOR-PREY MODEL WITH STAGE STRU

1
Introduction
Th e p red ator-pre y or com pe titive mod el with stage struc ture has rece ived mu ch atte ntion in re cen t years (se e [1- 10]). In th is p ape r, we classify in dividu als of prey an d pred ator into imm ature and mature . We assume th at matu re pre dators c an only pre y on im mature pre ys. In many pap e rs, h owe ver, th e au th ors assu med th at p red ators can on ly prey on matu re p reys. In [10], the mod el sim ilar to ou r assu mption bu t with out time de lay was stud ied: x�1 = αx 2 − γ 1 x 1 − β1 x 1 − η x2 1 − β 1 x 1 y, x�2 = β x 1 − γx 2 , y � = y ( − γ + β2 x1 − η 1 y ) . Th e optimal manage me nt of re ne wab le resou rces, wh ich h as a dire ct relation ship w ith sustainab le d evelop men t, h as b e en stu die d ex tensive ly b y many au thors. We con sid er the ex ploitation of a pre dator-p rey p opu lation with stage stru ctu re and h arvesting for mature pre y and pred ator. We b elieve th at su ch a p opu lation mod el is n ew in th is ﬁ eld. We obtain the con dition s for th e global asym ptotic stab ility of some non ne gative eq uilib ria and p erman en ce of th e pop ulation. In the n ext section , we p rop ose ou r mo de l and ob tain some resu lts on th e p ositivity an d b ou nd ed ne ss. Th e stability of equ ilib ria an d p erman en ce are con sidere d in S ec tion 3, followe d by a brief disc ussion in S ec tion 4.

英语六级巅峰阅读附详解第83期-健康与疾病

英语六级巅峰阅读附详解第83期:健康与疾病A study published in the New England journal of Medicine estimated that there are an average of 30 in-flight medical emergencies on U.S. flights every day. Most of them are not grave; fainting, dizziness and hyperventilation （换气过度) are the most frequent complaints, But 13% of them-roughly four a day-are serious enough to require a pilot to change course. The most common of the serious emergencies include heart trouble (46%), strokes and other neurological problems (18%), and difficult breathing (6%).Let's face it: plane riders are stressful. For starters, cabin pressures at high altitudes are set at roughly what they would be if you lived at 5,000 to 8,000 feet above sea level. Most people can tolerate these pressures pretty easily, but passengers with heart disease may experience chest pains as a result of the reduced amount of oxygen flowing through their blood. Low pressure can also cause the air in body cavities to expand-as much as 30%+ Again, most people won't notice anything beyond mild stomach cramping. But if you've recently had an operation, your wound could open. And if' a medical device hasbeen implanted in your body-a splint, a tracheotomy（气管切开术）tube or a catheter (导管)-it could expand and cause injury.Another common in-flight problem is deep venous thrombosis(深静脉血栓)-the so-called economy-class syndrome, When you sit too long in a cramped position. the blood in our legs tends to clot. Most people just get sore calves. But blood clots, left untreated, could travel to the lungs, causing breathing difficulties and even death. Such clots are readily prevented by keeping blood flowing; walk and stretch your legs when possible,Whatever you do, don't panic. Things are looking up on the in-flight-emergency front. Doctors who come to passengers' aid used to worry about getting sued; their fears have lifted somewhat since the 1998 Aviation Medical Assistance Act gave them"good Samaritan" protection. And thanks to more recent legislation, flights with at least one attendant are starting to install emergency medical kits with automated defibrillators (电击去颤器) to treat heart attacks.Are you still wondering if you are healthy enough to fly? If you can walk 150 it. or climb a flight of stairs without getting winded, you'll probably do just fine, Having a doctor close by doesn't hurt, either.一项刊登在《新英格兰医学杂志》上的研究估计，美国的航班平均每天发生30起飞行中的医疗急症。

高中英语 Unit 1 Great Scientists Section Ⅰ Pre-reading

Section ⅠPrereading (Warming Up & Reading)课前预习自测约翰·斯诺战胜“霍乱王”约翰·斯诺是伦敦一位著名的医生——他的确医术精湛，因而成为照料维多利亚女王的私人医生。

但他一想到要帮助那些得了霍乱的普通百姓时，他就感到很振奋。

霍乱在当时是最致命的疾病，人们既不知道它的病源，也不了解它的治疗方法。

每次暴发霍乱时，就有大批惊恐的老百姓病死。

约翰·斯诺想面对这个挑战，解决这个问题。

他知道，在找到病源之前，霍乱疫情是无法控制的。

斯诺对霍乱致人死地的两种推测都很感兴趣。

一种看法是霍乱病毒在空气中繁殖着，像一股危险的气体到处漂浮，直到找到病毒的受害者为止。

第二种看法是人们在吃饭的时候把这种病毒引入体内的。

病从胃里发作而迅速殃及全身，患者就会很快地死去。

斯诺推测第二种说法是正确的，但是他需要证据。

因此，在1854年伦敦再次暴发霍乱的时候，约翰·斯诺着手准备对此进行调研。

当霍乱在贫民区迅速蔓延的时候，约翰·斯洛就开始收集资料。

他发现特别在两条街道上霍乱流行得很严重，在10天之内就死去了500多人。

他决心要查明其原因。

首先，他在一X地图上标明了所有死者住过的地方。

这提供了一条说明霍乱起因的很有价值的线索。

许多死者是住在宽街的水泵附近(特别是这条街上16、37、38、40号)。

他发现有些住宅(如宽街上20号和21号以及剑桥街上的8号和9号)却无人死亡。

他以前没预料到这种情况，所有他决定深入调查。

他发现，这些人都在剑桥街7号的酒馆里打工，而酒馆为他们免费提供啤酒喝，因此他们没有喝从宽街水泵抽上来的水。

看来水是罪魁祸首。

接下来，约翰·斯诺调查了这两条街的水源情况。

他发现，水是从河里来的，而河水被伦敦排出的脏水污染了。

他马上叫宽街上惊慌失措的老百姓拆掉水泵的把手。

这样，水泵就用不成了。

不久，疫情就开始得到缓解。

外刊及中国日报精选文章改编：语法填空--高三英语三轮冲刺

外刊及中国日报精选文章改编：语法填空（答案+译文）第一篇世界首例！猪到人的异种肝移植临床手术在安徽完成The world's fifth living-body alien organ transplant, the first liver transplant from a pig to a living human, was successfully completed by the First Affiliated Hospital of Anhui Medical University on May 17,______ brings new hope to the over 140,000 domestic registered patients waiting for an organ transplant and the possibly higher number of unregistered people facing organ failure.________ a living person can donate part of his or her liver without sacrificing his or her life, the operation in Anhui province is still a significant development because compatible(兼容的) liver sources are not that easy _______(find) and a liver transplant________(involve) high medical costs and pain to get part of the liver from a donor. A liver transplant is even _________(complicated) than that of a heart and kidney that function as blood pump and water cycler respectively, as the liver is involved in metabolism, immunity, digestion and many more functions.The Anhui hospital's transplant operation is ________(medical) considered a success because the transplanted pig liver is reportedly operating normally in the patient's body, secreting 200 millilitres of gall every day._______ fact that cannot be omitted(遗漏) is that in previous cases the patients in the United Kingdom and the United States who received heart and kidney transplants(移植的器官) _______ pigs all passed away within two months after receiving the organs. The transplant operations have still prolonged the patients' lives and sustained them without a rejection reaction after the transplant operations till their _______(death). Further, the transplanted liver in the domestic case had only 10 genes edited to prevent a rejection reaction, fewer than the transplanted hearts and kidneys in the US and UK cases, which shows that domestic medical experts may have developed a methodology that can support the patient's _______(survive) without changing the liver too much.With the gene-editing technology aimed at "cutting" more gene clips that trigger a rejection reaction away from pig organs maturing, the risks of transplanted alien organsbeing rejected will be minimized and the technology will be applied more widely to save lives.第二篇社会：英格兰收养儿童的悲惨故事【经济学人】The sorry story of children in care in EnglandJADE BARNETT learned that she was being moved from foster c are(看护中心) into a children’s home a few years ago when she saw her possessions in the back of a taxi. The children’s home turned out ______(be) near Blackpool, in north-west England—330 kilometres from London, where she grew up and where the social workers who were meant to be lookingafter her were based. She expected to stay in the home for two weeks. It turned into one and a half years.Some 84,000 children in England are in the care of local authorities _______their parents cannot look after them for one reason or another. In an extremely centralised(集中的) country, it is one of the few important responsibilities that those _______( institution) still have. Every year councils spend more money on the children in their care. Every year the system serves the country’s most vulnerable children less well.Adult social care, including ________(nurse) homes for the old and frail, is notorious(臭名昭著的) for straining local authorities’ budgets. But spending on children in care is rising ________a faster rate, says Roger Gough, the leader of Kent County Council. In England as a whole, local authorities spent more than £7bn ($8.6bn) on looked-after children in the 2022-23 fiscal year, a 36% increase in real terms ________(compare) with 2015-16. That squeezes budgets for everything else, including help for families not yet in crisis.Over the ten years to 2023 the number of children in care swelled(增加) by 23%, or by 16%if you do not count unaccompanied children seeking asylum（庇护）, _______numbers have risen recently. And the children who enter the care system are becoming older and needier. Whereas(然而) young children tend to live with foster carers, older ones are more likely to end up inchildren’s homes; some require intensive, round-the-clock attention. Caring for them can be costly—sometimes amazingly costly.The Local Government Association estimates that in the 2018-19 fiscal year, England had 120 children who were each costing local authorities at least £10,000 per week. By 2022-23 the number had jumped to 1,500. One explanation is that local authorities are now looking after some teenagers who might once have ended up in psychiatric wards（精神病病房）or young offenders’ institutions. Over the past two decades the number of children in custody________(go) from 2,800 to around 400, reflecting not only less youthful offending but also a growing reluctance(不情愿) to lock them up.But the main reason for the increase in costs is economics. “It’s simply a supply-and-demand issue,” says Stuart Ashley, the head of children’s services for Hampshire County Council. England has too few foster carers _______ too few children’s homes. Councils end up competing for scarce places, with predictable consequences.England has a “mixed model” of care (in Scotland the state plays a bigger role). About half of children________(place) in foster care by independent agencies, which charge local authorities for their services; four-fifths of children’s homes are privately run. To judge by the ratings they receive from inspectors, private homes are no worse than state ones. But they are often in the wrong places, because firms tend to build them where property is cheap (see map). North-West England has fewer inhabitants than London, but it has 746 children’s homes compared with 164 in the capital.第三篇经济：为什么花钱让妇女多生孩子是行不通的？【经济学人】Why paying women to have more babies won’t workAS BIRTH RATES plunge, many _______(political) want to pour money into policies that might lead women _______(have) more babies. Donald Trump has v owed(发誓) to dish out bonuses if he returns to the White House. In France, _______ the state already spends 3.5-4% of GDP on family policies each year, Emmanuel Macron wants to “demographically rearm(人口统计上的重新调整)” his country. South Korea is contemplating(考虑) handouts worth astaggering（难以置信的）$70,000 for each baby. Yet all these ________(attempt) are likely to fail, because they are built on a misapprehension(误解).Governments’ concern is ________(understand). Fertility rates(生育率) are falling nearly everywhere and the rich world faces a severe(严重的) shortage of babies. At prevailing birth rates, the average woman in ______ high-income country today will have just 1.6 children over her lifetime. Every rich country except Israel has a fertility rate beneath the replacement level of 2.1, at which a population is stable without immigration. The decline(减少) over the past decade________(be) faster than demographers(人口统计学)expected.Doomsayers such as Elon Musk warn that these shifts threaten civilisation_______(it). That is ridiculous, but they will bring profound(深刻的) social and economic changes. A fertility rate of 1.6 means that, without immigration, each generation will be a quarter smaller than the one before it. In 2000 rich countries had 26 over-65-year-olds for every 100 people _______(age) 25-64. By 2050 that is likely to have doubled. The worst-affected places will see even more dramatic change. In South Korea, where the fertility rate is 0.7, the population is projected to fall by 60% _______ the end of the century.The decision to have children is a personal one and should stay that way. But governments need to pay heed to rapid demographic shifts(人口变化). Ageing and shrinking societies will probably lose dynamism and military might. They will certainly face a ________(budget) nightmare(噩梦), as taxpayers(纳税人) struggle to finance the pensions(养老金) and health care of legions of oldies.Many pro-natalist（亲出生主义者）policies come with effects that are valuable in themselves. Handouts for poor parents reduce child poverty（短缺）, for instance, and mothers who can afford child care are more likely to work. ________, governments are wrong to think it is within their power to boost fertility rates. For one thing, such policies ________(found) on a false diagnosis(判断) of what has so far caused demographic decline. For another, they could cost more than the problems they are designed to solve.One common assumption is that falling fertility rates stem from professional women________(put) off having children. The notion that they run out of time to have as many babies as they wish before their childbearing years(生育年龄) draw to a close explains why policies tend tofocus on offering tax breaks and subsidised child care. That way, it is argued,women do not have to choose between their family and their career.That is not the main story. University-educated women are indeed having children later in life, but only a little. In America their average age at the birth of their first child has risen from 28 in 2000 to 30 now. These women are having _______(rough) the same number of children as their peers did a generation ago. This is a little below what they say is their ideal family size, but the gap is no different from ________ it used to be.答案第一篇：Which Although to find involves more complicated medically A from deaths survival第二篇：to be because institutions nursing at compared whose has gone and are placed第三篇：politicians to have where attempts understandable a has been itself aged by budgetary However are founded putting roughly what译文第一篇：5月17日，安徽医科大学第一附属医院成功完成了世界上第五次活体外来器官移植，这是第一次猪向活人的肝移植。

第05讲读后续写之“助人类”主题(练)(解析版)

►第05讲助人类（练）目录_____________________________________________________________________1．（2023·湖南长沙·湖南师大附中校考一模）阅读下面材料，根据其内容和所给段落开头语续写两段，使之构成一篇完整的短文。

The chain of kindnessThe rain was coming down so hard that each drop seemed to explode as it hit the roof of the car. Tom looked out into the coal-black night, struggling desperately to keep his car on the road. The rain beatdown continuously and the road was deserted except for Tom and his car.Tom could see his wheelchair in the backseat from the rear-view mirror and quickly looked down at his thin, broken legs. He could feel a familiar wave of despair start to wash over him. Suddenly, a loud noise shook him out of his moment of hopelessness as the car began to bump down the road. “Great,” he thought, “a flat tyre.”With a heavy sigh, Tom brought the car to a stop, resting his head on the steering wheel, defeated! After a few seconds, he looked up and peered out of the window. In the distance, he could see a light twinkling in the blackness.When Tom approached the house, a young girl around ten years old was standing in the doorway. He pulled up and rolled down the window. “Are your parents at home?” he shouted over the wind and rain. “I have a flat tyre and I need help.”“Wait a minute,” the girl replied and went into the house. A few minutes later, she returned with an old man. The girl held his arm and smiled lovingly up at him.Tom explained the problem to the old man and added, “I need help because my legs are paralyzed.” The words came out flat. But he did not know how else he could convey the fact that he needed help from this weak old man in the middle of the rainstorm. The old man simply nodded.The old man and the little girl concentrated on their work and the rain was soaking them. Once again, Tom couldn’t help but feel he was useless. Soon the old man stepped to the window. “You’re all set,” he said. Tom handed some money to the old man, but he made no move to take it. Finally, the young girls aid, “Grandfather is blind.”注意：1.续写词数应为150左右；2.请按如下格式在答题卡的相应位置作答。

2021届湖南省长沙市雅礼中学高三下学期高考一模考试英语试卷及答案

2021届湖南省长沙市雅礼中学高三下学期高考一模考试英语试卷★祝考试顺利★(含答案)第二部分阅读（共两节，满分50分）第一节（共15小題：每小题2.5分.满分37. 5分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项。

AHere is a guide to the best countries to see the Northern Lights, as well as top tips such as the best time to go.★ Where to go： GreenlandKangerlussuaq is often regarded as the best spot in Greenland, with over 300 nights of clear skies. Alternatively, you can visit the capital city of Nuuk, where on clear nights, there have been plenty of sightings of the Northern Lights. And in the southern regions, darkness tends to fall earlier in the evening, ideal for those who don’t want to stay up all night.Best time to go： From November through to April.★Where to go： NorwayHead to the northern regions of Norway for the best possible chances of seeing the Northern Lights. Head to Svalbard, one of the world’s northernmost inhabited areas，and you,II feel like youVe stepped into an ice kingdom. Those who love the great outdoors might want to check out the Lyngenfjord region, where you^l find plenty of tours to see the Northern Lights, whale-watching, skiing, ice climbing and so on!Best time to go： From October through to March when the polar nights make them easier to spot.★ Where to go： SwedenHead to Abisko National Park where the clear skies and lack of light pollution make for ideal Northern Lights viewing conditions. One of the best spots is in SwedishLapland, where you can have dinner under the midnight skies. Hikers might also consider trying the Kungsleden hiking trail, which offers about 440km of breathtaking landscapes.Best time to go： From September through to March.★Where to go： IcelandYou don t need to go to the remote landscapes to spot the Northern Lights. In fact, sightings are possible from Iceland's capital of Reykjavik. Want to escape the crowds? Head to lesser-known spots such as Thingvellir, which is the place where photographerstry to capture the perfect Northern Lights photo.Best time to go：From late August to mid-April, although you will increase your chances if you visit from late September through to March.21．What can we learn about Greenland from the text?A．It has one of the worlds northernmost inhabited areas.B．It offers an about 440km of hiking trail with breathtaking landscapes.C．The capital city of Nuuk is the only place to see the Northern Lights in Greenland D．One can go to the southern regions in order to see the Northern Lights earlier. 22．We can learn from the text that .A．most cities in Greenland have over 300 nights of clear skies a yearB．one can see the Northern Lights as well as whale-watching in the Lyngenfjord region C．one can have dinner under the midnight skies in ThingvellirD．late September through to March is the best time to see the Northern Lights in Norway 23．The text has been written for those who .A.intend to study the Northern LightsB. want to see the Northern LightsC. are interested in European countriesD. are fond of extreme sportsBAlbert Einsrein is known as the father of modern physics, but he may not be the man your kids should aspire(有志) to be. Instead, the person we should be looking upto is the productive Thomas Alva Edison.Researchers at Penn State and William Paterson universities came to that conclusion after conducting a series of studies with college students and finding that students were more motivated by the hard-working Edison type than Einstein’s “genius(天才) is my birthright” model.“There's a misleading message out there that says you have to be a genius in order to be a scientist，” says study co-author Danfei Hu at Penn State, who thinks this may be a big cause of people not choosing science and missing, out on a great career. "Struggling is a normal part of doing science and exceptional talent is not the only precondition for succeeding in science! It's important we help spread this message in science education.” she continues.In one study conducted by Hu and Janet N. Ahn of William Paterson University, participants read the same story--about the typical difficulty faced by a scientist -- with half told the hero of the story was Einstein and the other half told it was Edison. It may have been the same story, but knowing it involved Einstein prompted students to assume he overpowered his struggles using his giant brain. When told Edison was the hero, students more with the idea that he outworked his problems. Indeed, the latter students were more motivated to complete a series of math problems.Einstein’s success is commonly linked to extraordinary talent while Edison’s is usually linked to his persistence and diligence. That’s not to say Einstein put little effort into revolutionizing science. He worked as hard as anyone. But the popular understanding remains that his brain --something that can’t be “emulated”--was like no other. So why bother trying to follow in his footsteps? Edison, however, a man with a huge number of successes as well as plenty of failures, but finally someone who made the world a better place, is the kind of man we can all aspire to be.24．What did the researchers discover in their studies?A. Hard workers are better role models than geniuses.B. Young people have unreasonable admiration for geniuses.C. Edison's contribution to science is greater than Einstein’s.D. Young people are not familiar with Einstein’s and Edison’s work.25. What does Hu suggest in science education?vA. Setting examples.B. Encouraging failures.C. Advocating hardwork.D. Discovering talent.26. Which might be the author’s view on Einstein?A. Not productive but influential as a physicist.B. A genius who succeeded in science easily.C. A great physicist with many hidden virtues.D. well-known genius and an unacknowledged hard worker.27. The underlined word “emulated” can be replaced by “”.A. examinedB. copiedC. wastedD. damagedCThere are a lot of feral (野生的）camels in Australia. Although they don't appear to be as destructive as other introduced species because they eat trees and plants that our native Australian animals don't eat, in the last few years the Australian Camel population has been increasing at a fairly alarming rate and becoming a bit of a problem.We didn't see them that often where we grew up unless we went further into Queensland or South Australia. When we did see them it was always a bit of a thrill for us kids because it was somewhat of a novelty.The suggestion of bringing camels to Australia was first made in 1837, 49 years after Europeans arrived in Australia. The importing of camels into Australia began in the mid 1800s to open up the desert areas of Cental and Western Australia. They were handled and cared for by Muslim cameleers that came from countries like Egypt, Turkey and northern India. The cameleers were called Afghans or "Ghans" even though most of them were not Afghans. The name stuck to a part of the railroad track that links Port Augusta in South Australia to Darwin in the Northern Territory.In a famous 176-kilometre race, between Bourke and Wanaaring in New South Wales a camel was beaten by a horse but the horse diet the next day while the camel was ridden back to the starting point.By the 1920s there were about 20, 000 domesticated(家养的)camels in Australia, but with the arrival of motor and rail transport in the 1930s people no longer needed their camels and a lot of them were abandoned in the bush.Australian Camels are now exported live to Saudi Arabia, the United Arab Emirates and other countries where disease-free camels are considered a delicacy (佳肴).Australian Camels are also exported to Arab Camel racing stables as breeding stock. The United States also imports them to use in tourist attractions. There are over 40 farms providing rides in Australia now.28.What problem with camels in Australia is mentioned?A. They carry disease.B. They hurt people sometimes.C. The number of them is growing rapidly.D. Some native animals are threatened by them.29. For what purpose were camels brought to Australia?A. To keep the balance of nature.B. To develop the desert areas.C. To satisfy kids' curiosity.D. To create new jobs.30. What led to camels' being deserted in Australia?A. The disappearance of bushes.B. The spread of a serious disease.C. The introduction of other animals.D. The availability of modern vehicles.31. What is the last paragraph mainly about?A. The history of Australian Camels.B. What Australian Camels are used for.C. The advantages of Australian Camels.D. Why Australian Camels are popular abroad.DAn unconventional method for growing rice has been found to increase yields(产量)by 20 to 50 percent. Reports from China, India, Southeast Asia and Africa suggest that average yield increases of 20 to 50 percent are regularly being achieved by farmers adopting the "system of rice intensification (集约化）” (SRI), which needs one-tenth as many and seeds and aims to stimulate the root system of plants rather than trying to increase, yields in the conventional way by using improved seeds and fertilizers.The idea of using less to gain more is seen as an important innovation (革新）foradapting farming to climate change and a way to increase yields at a time when human populations are growing fast but traditional plant breeding and genetically modified techniques have failed to increase yields more than a few percentage points, says Norman Uphoff, professor of international agriculture at Cornell.The new way to grow rice needs only half as much water, and is proving most popular in water-stressed countries, says Tavseef Mairaj Shah, a Ph.D. researcher. “Rice growing in Kashmir largely depends on irrigation systems that draw water from the river Jhelum. But climate change is leading to drier winters，untimely rains, and warmer summers.”“SRI is a great technique, not just from the water-saving perspective but because it offers better yields and soil conditions. Different studies, both at the experimental level and farmer-participative level, have shown that SRI improves yields with less water.” Shah adds.Some academics, the global seed industry and the' international community once rejectedreports of “fantastic”yields,accusing farmers of falsifying(篡改）records and researchers of carelessness and “non-science” . But more than 600 articles, checked by SRI international at Cornell University, have shown benefits.Uphoff says, ”Attitudes are changing. The original hostility(敌意)has gone.” However, the early opposition has resulted in comparatively little scientific research being conducted into SRI and a slow understanding by funders.32. How does SRI increase the yields of rice?A.By sowing more seeds.B. By using improved seeds.C. By improving its root system.D. By adopting special fertilizers.33. Compared with the conventional method for growing rice, SRI .A. 2needs less waterB. increases labor costsC. requires better soil conditionsD. depends on genetically modified techniques34. What was the global seed industry's initial attitude toward reports on SRI?A. Curious.B. Skeptical.C. Approving.D. Uninterested.35. Which of the following can be the best title of the passage?A. How to Increase YieldsB. People's Attitudes Towards SRIC. An Innovative Means of Growing RiceD. The Disadvantages of Conventional Plant Breeding第二节（共5小题；每小题2.5分，共12.5分）阅读下面短文，从短文后的选项中选出能填入空白处的锻佳选项。

损害身体健康行为英语作文

损害身体健康行为英语作文Smoking is a terrible habit that can cause serious damage to your health. It can lead to lung cancer, heart disease, and a range of other health problems. It's not worth the risk.Drinking too much alcohol can also be harmful to your body. It can damage your liver, increase your risk of accidents, and lead to addiction. It's important to drink in moderation and know your limits.Not getting enough sleep can have negative effects on your health. It can weaken your immune system, affect your mood, and increase your risk of chronic diseases. Make sure to prioritize sleep and get the recommended amount each night.Eating a diet high in processed foods and sugar can be detrimental to your health. It can lead to obesity, diabetes, and other health issues. It's important to eat abalanced diet with plenty of fruits, vegetables, and whole grains.Neglecting to exercise regularly can also harm your health. It can lead to weight gain, muscle loss, and a higher risk of chronic diseases. Make sure to incorporate physical activity into your daily routine to stay healthy.Ignoring mental health issues can also have serious consequences. Depression, anxiety, and other mental health disorders can impact your overall well-being. It's important to seek help and support when needed to take care of your mental health.In conclusion, it's important to be mindful of your behaviors and how they can impact your health. By avoiding harmful habits and taking care of your body and mind, you can lead a healthier and happier life.。

德尔塔新冠病毒人体历险记作文

德尔塔新冠病毒人体历险记作文英文回答：Delta's Journey in the Human Body During the COVID-19 Pandemic.The Delta variant of the coronavirus has been causing havoc around the world, posing a threat to public health. Let's take a closer look at Delta's journey in the human body during the COVID-19 pandemic.Delta first enters the body through respiratory droplets when an infected person coughs, sneezes, or talks. These droplets contain the virus and can be inhaled by others nearby. Once inside the body, Delta quickly attaches itself to the ACE2 receptors on the surface of human cells, particularly in the respiratory system.Once attached, Delta begins to replicate rapidly, producing more viral particles. This high rate ofreplication is one of the reasons why Delta is highly transmissible. As the virus multiplies, it spreads to other parts of the respiratory system, including the lungs. This can lead to severe respiratory symptoms, such as coughing, shortness of breath, and pneumonia.Delta's ability to evade the immune system is another concerning aspect. It has mutations in the spike protein, which is the target of most COVID-19 vaccines. These mutations allow Delta to partially escape the immune response triggered by vaccination or previous infection. As a result, even vaccinated individuals can become infected with Delta, although they are more likely to experience milder symptoms.As Delta continues its journey in the body, it can also spread to other organs, such as the heart, liver, and kidneys. This can lead to complications and increase the severity of the disease. Additionally, Delta can cause an overactive immune response, leading to a condition called cytokine storm. This excessive immune response can damage multiple organs and even be life-threatening.In the later stages of the infection, Delta may also affect the gastrointestinal system, causing symptoms like diarrhea, nausea, and vomiting. This highlights the diverse range of symptoms that can occur with Delta infection.中文回答：德尔塔新冠病毒人体历险记。

中考英语身体发育单选题50题

中考英语身体发育单选题50题1. Our eyes are very important for us. We should protect them well. ______ is bad for our eyes.A. Reading in strong sunlightB. Doing eye exercises every dayC. Having enough sleepD. Eating more vegetables答案：A。

解析：本题考查对眼睛健康有影响的行为。

选项A在强烈阳光下阅读对眼睛是有害的，因为强光会伤害眼睛；选项B每天做眼保健操对眼睛有益，不符合题意；选项C有足够睡眠对眼睛健康有好处，不是有害行为；选项D多吃蔬菜对身体包括眼睛都有好处，也不符合题意。

2. The heart is like a powerful pump in our body. It ______ blood to all parts of the body.A. sendsB. receivesC. stopsD. loses答案：A。

解析：本题考查心脏的功能相关的动词用法。

心脏是把血液输送到身体各个部位，send有发送、输送的意思，符合题意；选项B receive是接收的意思，与心脏功能不符；选项C stop是停止，心脏不是停止血液而是输送血液；选项D lose是失去，也不符合心脏功能。

3. When we run, our lungs need more oxygen. So we should ______ deeply.A. eatB. drinkC. breatheD. think答案：C。

解析：本题考查与跑步时肺部需求相关的动词。

当我们跑步时，肺部需要更多氧气，所以我们应该深呼吸，breathe是呼吸的意思，符合语境；选项A eat是吃，与呼吸氧气无关；选项B drink 是喝，也和呼吸氧气没关系；选项D think是思考，不符合题意。

发烧的英文短语

发烧的英文短语**Title: Understanding Fever****Introduction:**Fever, a common yet often misunderstood bodily response,serves as a crucial indicator of underlying health conditions. In this comprehensive document, we delve into the intricacies of fever, exploring its definition, causes, symptoms, and management. By understanding fever in-depth, individuals can better navigate its presence and seek appropriate medical attention when necessary.**What is Fever?**Fever, medically known as pyrexia, is defined as an elevated body temperature above the normal range, typically around98.6°F (37°C). This rise in temperature occurs due to the body's response to infections, inflammation, or other physiological disturbances. It serves as a protective mechanism, aiding the immune system in combating pathogens.**Causes of Fever:**Fever can stem from various factors, including viral or bacterial infections such as influenza, urinary tract infections, or pneumonia. Additionally, autoimmune disorders, inflammatory conditions, and certain medications may trigger fever. Understanding the underlying cause is crucial for effective management.**Symptoms Associated with Fever:**Apart from the elevated body temperature, fever oftenmanifests with accompanying symptoms. These may includechills, sweating, headache, muscle aches, fatigue, and lossof appetite. The severity and duration of these symptoms can vary depending on the underlying cause of the fever.**Types of Fever:**Fever can be categorized based on its duration and pattern. Acute fevers occur suddenly and typically resolve within a few days, often indicating an infection. Subacute fevers last longer, usually between one to two weeks, and may signify a more chronic condition. Chronic fevers persist for an extended period, often indicating underlying health issues that require thorough investigation.**Managing Fever:**Treatment for fever aims to alleviate discomfort and address the underlying cause. Over-the-counter medications such as acetaminophen or ibuprofen can help reduce fever and relieve associated symptoms. However, it's essential to consult a healthcare professional, especially if the fever is persistent, accompanied by severe symptoms, or occurs in infants, elderly individuals, or those with weakened immune systems.**Home Remedies and Self-care Measures:**In addition to medication, several home remedies and self-care measures can aid in managing fever. These include staying hydrated, getting plenty of rest, applying cool compresses to reduce body temperature, and avoiding excessive physical exertion. Moreover, maintaining good hygiene practices and practicing proper infection control can prevent the spread of infectious diseases causing fever.**When to Seek Medical Attention:**While most fevers resolve on their own or with minimalintervention, certain red flags warrant immediate medical attention. These include fever in infants younger than three months, persistent fever above 103°F (39.4°C), feverlasting longer than three days, or fever accompanied by severe symptoms such as difficulty breathing, confusion, or persistent vomiting.**Conclusion:**In conclusion, fever serves as a vital physiological response indicating underlying health conditions. By understanding its causes, symptoms, and management strategies, individuals can effectively navigate through episodes of fever and seek appropriate medical care when necessary. Remember, while fever itself is often a benign phenomenon, it's crucial to monitor accompanying symptoms and seek prompt medical attention if needed. Stay informed, stay vigilant, and prioritize your health.。

高中英语真题-吸二手烟有损儿童的动脉

高中英语真题:吸二手烟有损儿童的动脉Passive smoking causes lasting damage to children's arteries, prematurely ageing their blood vessels by more than three year s, say researchers.研究人员称，吸二手烟会对儿童的动脉造成持续伤害，使他们的血管老化三年以上。

The damage - thickening of blood vessel walls - increases the ri sk of heart attacks and strokes in later life, they say in the Euro pean Heart Journal.In their study of more than 2,000 children aged three to 18, the harm occurred if both parents smoked.Experts say there is no "safe" level of exposure to second-hand smoke.The research, carried out in Finland and Australia, appears to r eveal the physical effects of growing up in a smoke-filled home - although it is impossible to rule out other potentiall y contributory factors entirely.Hidden damageUltrasound scans showed how children whose parents both sm oked developed changes in the wall of a main artery that runs u p the neck to the head.While the differences in carotid intima-media thickness were modest, they were significant and detect able some 20 years later when children had reached adulthood, say the investigators.Study author Dr Seana Gall, from the of , said: "Our study sho ws that exposure to passive smoke in childhood causes a direct and irreversible damage to the structure of the arteries."Parents, or even those thinking about becoming parents, shoul d quit smoking. This will not only restore their own health but al so protect the health of their children into the future."The results took account of other factors that might otherwise e xplain the association, such as whether the children went on to be smokers themselves, but the findings remained unchanged.However, if only one parent smoked the effect was not seen - p ossibly because exposure was not as high.Dr Gall said: "We can speculate that the smoking behaviour of s omeone in a house with a single adult smoking is different. For example, the parent that smokes might do so outside away fro m the family, therefore reducing the level of passive smoking. H owever, as we don't have this type of data, this is only a hypoth esis."Regardless, experts say all children should be protected from s econd-hand smoke.Doireann Maddock, senior cardiac nurse at the British Heart Fo undation, said: "The negative health effects of passive smoking are well known, but this study goes a step further and shows it can cause potentially irreversible damage to children's arteries i ncreasing their risk of heart problems in later life.吸二手烟有损儿童的动脉Passive smoking causes lasting damage to children's arteries, prematurely ageing their blood v essels by more than three years, say researchers.研究人员称，吸二手烟会对儿童的动脉造成持续伤害，使他们的血管老化三年以上。