2017年12月英语四级语法从句复习

　　1.目的状语从句

　　可以由that，so that，in order that，lest，for fear that，in case等词引导;

　　lest：以防，从句中的谓语动词必须用should+动词原形;

　　eg: He wrote the name down for fear that(lest) he should forget it.

　　He took the umbrella with him lest it should rain.

　　in case：以防，与lest不同，从句里的时态不做特殊变化;

　　eg：Take the umbrella with you in case it rains.

　　for feat that：和lest保持一致;

　　eg：A variety of activities should be organized so that participants can remain active as long as they want and then go on to something else without feeling guilty and without letting the other participants down.

　　let…down…：让……感到气馁。

　　2.结果状语从句

　　结果状语从句常由so… that 或 such…that引导;so保留，that可以省略;如此……以至于……;

　　eg：He didn't abide by the contract so that he was fined.

　　He was so excited that he couldn't fall asleep.

　　He made such an inspiring speech that everybody got excited.

　　比较：so和 such

　　(1)so：so +形容词、副词+that;so+形容词+a/an+名词+that;

　　eg：The wind was so strong that we could hardly move forward.

　　He run so fast that I couldn't catch up with him.

　　It was so hot a day that crops wilted.

　　He is so lovely a boy that everyone loves him.

　　(2)such：such+a/an+形容词+名词+that

　　eg：It was such a hot day that crops wilted.

　　He is such a lovely boy that everyone loves him.

　　3.比较状语从句：

　　than，as…as…，not so as…，(not) the same as，the+比较级;

　　eg：Light travels fast than sound.

　　the+比较级：

　　eg：The sooner，the better.

　　(1)当……的时候：while，when，as ;

　　when：强调一件事情正在发生的时候，另外一件事情突然发生;

　　eg：When I was watching TV, my mother came back.

　　while：强调两个动作同时进行，一边……一边……;

　　eg：My father is cooking while my mother is reading newspaper.

　　as："随时间推移"

　　eg：As time went by, the days became longer and longer.

　　(2)一……就……：as soon as，主将从现;用directly，immediately， instantly连接两个句子;一些名词如the minute，the moment，the instant也可表示;no sooner… than，hardly… when后面的句子需要倒装;

　　eg：I will write to you the moment/minute I arrived in Paris.

　　(3)特殊单词：by the time that，every/each time(使用时后面不要再加when)

　　(4)till&until：

　　① 肯定形式表示的意思是"做某事直至某时"，动词必须是延续性的;

　　否定形式表达的意思是"直至某时才做某事"，一般用until，动词为延续性或非延续性都可以;

　　eg: I slept until midnight.

　　Wait till I call you.

　　She didn't arrive until 6 o'clock.

　　② Until可用于句首，而till通常不用于句首，通常用于句中;

　　eg: Until you told me, I had heard nothing of what happened.

　　eg：As you sleep you pass through a sequence of sleep states—light sleep, deep sleep and REM (rapid eye movement) sleep—that repeats approximately every 90 minutes.