常见重要句型

常见重要句型
1．It was （not ）+ 时间段+before +一般过去时过了一段时间就……．．
It will （not ）be+ 时间段+before +一般现在时要过一段时间才会…
It is/ has been +时间段+ since…．．
It was +点时间+ when…．．
It was +时间状语+ that …．．（强调句）
1）．It was not long before he sensed the dangerof the position．不久他就意识到他处境危险
2）．It will be half a year before you graduatefrom the school．还有半年你才从这个学校毕业
3）．It is 3 years since he worked here．=he left here．（since从句中的谓语动词若是延续性动词，要从这个动作结束的时候算起）
4）．It was 3 o’clock when they received thetelephone．
5）It was at 3 o’clock that they received thetelephone．
2．once…．．一旦…．．，表示时间和条件
1）Once you understand what the teacherexplained，you will have no difficulty doingthe work．
2）．Once you have decided to do something，you should finish it and do it well．3．The +比较级……．，the +比较级……．．越……，越……
1）The more books you read，the more knowledge you will get．
2）The busier he is，the happier he feels．
4．as if/ as though…．．（表示与事实相反，用虚拟；若表示即将成为事实或有可能成为事实，则用陈述语气）
1）．He was in great trouble，but he acted as if nothing had happened．2）．Although they just met for the first time，they talked as if they had been friends formany years
3）．The clouds are gathering．It looks as if it is going to rain．
5．n．/adj．/ adv．/ v．+ as / though +主语+谓语，尽管……，……．引导让步状语从句
1）．Child as he is，I already know what career I want to follow．
2）．Try as he might，he couldn’t solve the problem．
3）．Much as I respect him，I can’t agree with his idea．6．whether…．or…．无论是…．还是…．
1）．Whether the weather is good or bad，they will set off as they planned．2）．Any person，whether young or old，has his own worth．
7．疑问词+ever = no matter +疑问词，引导让步状语从句或名词性从句
1）．Whichever（=Nomatter which）you like，you can take it away ．（让步状语从句）
Youcan take away whichever（=anyone that）you like （名词性从句）2）．Whenever you comes，you will be welcome．（让步状语从句）3）．Whatever happens，I will support you．（让步状语从句）4）．Whoever breaks the law，he will certainly be punished．（让步状语从句）Whoeverbreaks the law will certainly be punished．（名词性从句）5）．However great the difficulty is，we can overcome it．（让步状语从句）8．as long as/so long as/ providing that/ provided that/ supposing that/on condition that 假如…．．
1）．I will lend you money on condition that youcan return it within 3 months．9．in case that/ in case of…．．万一…．．，以防…．．
1）．In case of fire，please dial 119 at once．
2）．In case that John comes/ John should come，tell him to wait．
10．祈使句+ or/otherwise +结果句或祈使句+ and +结果句
1）．Stop doing such foolish thing，or you will be punished in time．2）．More effort，and the problem would have been settled．
3）．Think it over，and you will find the answer．
11．so/ such……．．that……．引导结果状语从句时须注意
当名词前many，much，little，few有修饰时，用so不用such因为此时的中心词不再是名词，而是many，much，little，few这些表示数量的词。

1）．The westerners eat so much fat and sugarthat they put on weight easily．
2）．There are so few fish in the lake that wecouldn’t fish them easily．
当名词是单数可数名词，前面又由adj．修饰时，注意冠词的位置，即so+ adj +a （n）+n或such+ a（n）+ adj．+ n
1）．He is such an honest person/ so honest aperson that you can depend on him when you are in trouble．当so/such引导的部分位于句首时，主句要用部分倒装结构
1）．Such great progress has he made in hisstudies that we all admire him．
当主从句主语一致时可与动词不定式相互转换，即变成so/such……．as to do结构。

1）．The westerners eat so much fat and sugar asto put on weight easily．
12．so that 引导目的状语从句与结果状语从句
so that引导目的状语从句时常与情态动词连用（= in order that），当主从句主语一致时可转换为so as to do/ in order to do．
1）．He turned up the radio a little so that hecould hear the news clearly．
He turned up the radio a little so as to hear the news clearly．
2）．He closed all the windows while driving sothat he shouldn’t catch cold．（否定句中情态动词用shouldn’t）
so that 引导结果状语从句一般不与情态动词连用
1）．He turned up the radio a little so that heheard the news clearly．。