高三英语： 动词时态-完成体之现在完成时

2. 与笼统地表示过去的时间状语连用
如: just, already, yet, before I've just found this library book. I have already read that book. I haven’t finished that book yet.
3. 与表示从过去持续到现在的一段时 间的状语连用
动词时态-完成体 之现在完成时 Present perfect
作者 李某某
Objectives
1. 理解完成体及现在完成时的基本含义 2. 掌握现在完成时的用法 1) 熟记与现在完成时连用的时间状语 2) 区分终止性动词与延续性动词的用法 3) 理解现在完成时与一般过去时的区别， 能根据具体语境恰当选用时态
Pick out predicates in the present perfect tense (现在完成时）, and think why they are used in this tense?
has decided, have developed, have
revolutionized, have provided 1. 过去发生的事情对现在的影响 （终止性动词）
常与现在完成时连用的时间状语
1. 与表示现在的时间状语连用 如: now, today, this week, this month, this
year 等 The rain has stopped now. Have you seen John today? I have been there only once this year.
have plagued …(for millennia) 2. 过去的动作或状态持续到现在 （延续性动词）
现在完成时的基本含义
1. These two discoveries have provided humankind with poweห้องสมุดไป่ตู้ful new means to combat(作战) these diseases.
Aspect 体
一般体- 动作发生或状态存在的事实 进行体- 动作正在进行或状态正在持续 完成体 完成进行体-
Read the press release(新闻稿）, and underline all the predicate (谓语).
Press Release 2015-10-05
如: recently, lately, in the past few years, these few years, these days, up to now, so far, for + 时间段, since+时间点 等
How have you been recently?
The famous writer has written a new book in t he past two years.
2. Diseases caused by parasites (寄生虫) have plagued (折磨) humankind for millennia(数千 年)。
现在完成时表示__过__去___发生的动作或状态， 导致_情__景____ 变化，这种变化持续到_现___在___。 现在完成时常用于_新__闻____ 、 学__术___写__作__ 及 _对__话___等体裁中。
These two discoveries have provided humankind with powerful new means to combat(作战) these debilitating(使 人虚弱的) diseases that affect hundreds of millions of people annually. The consequences in terms of improved human health and reduced suffering are immeasurable.
and the other half to Youyou Tu
for her discoveries concerning a novel therapy against Malaria （疟疾）
Diseases caused by parasites (寄生虫) have plagued (折 磨) humankind for millennia(数千年) and constitute(构成， 成为) a major global health problem. In particular, parasitic diseases affect the world’s poorest populations and represent a huge barrier to improving human health and wellbeing. This year’s Nobel Laureates(桂冠，获奖者) have developed therapies that have revolutionized the treatment of some of the most devastating parasitic diseases.
The Nobel Assembly(大会) at Karolinska Institutet (卡罗林斯卡医学院) has today decided to award the 2015 Nobel Prize in Physiology or Medicine
with one half jointly to William C. Campbell and Satoshi Ōmura for their discoveries concerning a novel therapy against infections caused by roundworm parasites(蛔虫）