用法小结

⑴

⑵

⑶.

⑷

⑸

⑹

⑺

注意的几个it 句式

1.It is \was the first time that S+ have \ had done . （ 这是第...次.....）

2. It is high time that S+ should do \ did sth (到....时间)

3. It is + 短时间 since S+ did . (这件事发生.....久)

4. It won't be long before S+ do (不久 ......)

5. 强调句式： It was \ is ..........that \who........... (注意检测办法)

Do Exercises

1. _____ as much as one-fifth of all timber harvested is not used.

A. The estimate B. The estimate

C. They are estimated D. It is estimated that

2. _____ some mammals came to live in the sea is not known.

A. Which B. Since C. Although D. How

3. _____ we have achieved is attributed to the guidance of our parents.

A. Whoever B. Whatever C. However D. That

4. _____ wealthy does not necessarily mean that a man is greedy.

A. For the reason that he is B. Just because he is

C. The reason of being D. That he is

5. Although _____ happened in this developed country sounds like science fiction, it could occur elsewhere in the world.

A. which B. what C. how D. it

6. _____ she had forgotten to take her notebook.

A. That occurred to her B. She occurred that

C. To her that occurred D. It occurred to her that

7. I am sure that _____ she said is wrong.

A. which B. all C. this D. what

8. We lost our way in the forest, and _____ made matters worse was that it was getting dark.

A. that B. which C. it D. what

9. _____ some mammals came to live in the sea is not known.

A. Which B. Since C. Although D. How

10. _____ or not is still uncertain.

A. He's coming B. If he is coming

C. That coming D. Whether he's coming

11. It's _____ he'll be able to come.

A. doubt whether B. doubtful C. doubt it D. doubtful whether

12. _____ he is at work in the heart of the big city or at home in the quiet suburb, Dick's life is tied to machines.

A. Whether B. Till C. If D. Unless

13. _____ he saw both surprised and frightened him.

A. That B. When C. What D. Which

14. _____ is a spell of warm sunshine.

A. What do we all need. B. What all we need

C. What we need D. What we all need

15. _____ is a pity that he should feel so upset.

A. What B. That C. He D. It

16. _____ a spoonful of soil can tell us so much about the structure and early history of the moon.