1. 用于省略 if 的虚拟条件状语从句： 条件状语从句主句 与现在事 实相反 If+ 主语 +Ved (be 动词一律用 were) 主语 +would/could +V 原 与现在事 实相反 If+ 主语 + had done 主语 +would/could +have done 与现在事 实相反 A: 谓语用 Ved B: were to do C: should + V 原 主语 +would/could +V 原

2. If 的省略 : 当从句中有 were, had 或 should 时, 可省略 if, 将 were, had 或 should 提到主语前, 构成半倒装形式. (1)Were/Should/Had+ 主语 +(not) 其他成分 =If+ 主语 +were/should/had+(not) 其他成分 If he were my friend, I would expect his help. If it should rain tomorrow, I should stay indoors. If you hadn ’ t told me about it, I should never have known the whole thing.

3. (2) Were it not for/Had it not for +n. =If it were not for/hadn ’ t been for +n. If it were not for their help, we would be in serious trouble. If it hadn ’ t been for their support, we couldn ’ t have won the election.

4. 用于让步和原因状语从句 ( 将表语, 动词或副词状语提前 ) 形容词 名词 ( 前无冠词 ) 表原因 :as( 或 that) 系动词 分词 + + 主语 + 情态动词 动词 表让步 :as( 或 though) 助动词 副词 谓语动词 Strange though it may seem, the tallest boy is the youngest. =Although it may seem strange, the tallest boy is the youngest.

5. Tired that he was, he went to bed early. =Because he was tired, he went to bed early. Woman as she is, she courageous. =Although she is a woman, she is courageous. Coward as he was, he ran away as soon as the enemy attacked. =Because he was a coward, he ran away as soon as the enemy attacked.

6. Surrounded as he was by the enemy, he was not afraid. =Although he was surrounded by the enemy, he was not afraid. Absorbed as he was in the book, he did not notice my entering the room. =Because he was absorbed in the book, he did not notice my entering the room. Try as he would, he might fail again. =Although he would try, he might fail again.

7. Hard as he studies, he cannot pass the exam. =Although he studies hard, he cannot pass the exam. Much as I like you, I will not marry you. = Although I like you much, I will not marry you.

8. so..that.., such..that.. 的句子结构中 若 so, such 和与其所修饰的词置于句首，实 行部分倒。 So frightened was she in the darkness that she didn’t dare to move. So many questions did they ask me that I got confused. So much does he worry about his position that he cannot sleep at night.

9. Such a fierce dog did he have that we had to wait before we could get in. Such was the force of the explosion that all the windows were broken. 注意 : 如果 so/such 位于句首修饰主语时, 不倒装。 So few people came to his birthday party that he felt disappointed.

10. 程度副词在句首 此类副词如 : often, well, bitterly, gladly Often does he warn us not to touch the poisonous chemical. Well do I remember the days when we were at school together. Gladly would I give my life to save the child.

11. 带 To such … 表程度的状语在句首 To such a degree was he excited that he couldn’t go to sleep that night. To what degree are you interested in reading? To such lengths( 到这种详细的地步 ) did he speak that everyone got bored.

12. 用于 as 和 than 引导的状语从句 在 as 引导的方式状语从句和 than 引导的比较 状语从句中, 如果 as 和 than 从句的主语较长 或带有长的修饰语时, 可用半倒装. He traveled a great deal as did most of his friends. Harry is unusually tall, as are his brothers. I spend less than do nine out of ten people in my position.

13. 用于某些表示祝愿或口号的句子 : May you succeed! Long live Chairman Mao!

14. Exercises: 1. ___it rain tomorrow, we would have put off the visit to the Yangpu Bridge.(94) A Were B Should C Would D Will 2. So difficult _____ it to live in an English- speaking country that I determined to learn English well. (2001 上海卷 --- 27 ) A. I have felt B. have I felt C. I did feel D. did I feel

15. __________ that no fish can live in. A. So shallow is the lake B. So shallow the lake is C. So the lake is shallow D. So is the lake shallow (92 上海卷 ---14 )

16. _____,I have never seen anyone who's as capable( 有能力） as John.(2001) A As long as I have traveled B Now that I have traveled C Much as I have traveled D As I have traveled so much

17. ___, he knows a lot of things. A The child as he is B Child as he is C A child as he is D Child as he is

18. So fast _____ that it is difficult for us to imagine its speed. A. light travels B. does light travel C. light does travel D. will light travel

19. Difficult _______ the problem is, we should try to work it out. A. however B. as C. although D. that

20. School is twenty miles away. I would walk there, _______so far away. A. was it not B. it is not C. would it not be D. were it not

21. Angry ______ he was, he couldn ’ t help smiling. A. although B. as C. since D. because

22. .So busy ____ that he has no time to spare. A.he was B.was he C.he is D.is he

23. ____ happy. A.You may be B.May you be C.Be you may D.May be you

24. ____ as young as you, I would study hard. A. Was I B. Were I C. If I am D. If I was