主语从句作为考察点是比较简单的，但是大家也需要通过语法主语从句提升练习来巩固知识点，希望做过练习后大家可以完全掌握主语从句。

单项选择题

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. _____ was once regarded as impossible has now become a reality.    A. That     B. Which      C. Who    D. What

3. _____ we have achieved is attributed to the guidance of our parents.    A. Whoever     B. Whatever     C. However      D. That

4. _____ you say now can’t make up for what you’ve done.     A. No matter     B. Whatever   C. However    D. That

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. _____ occurred to him that he had forgotten to lock the door when he left home.

A. This    B. It     C. That    D. These 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. It is _____ that the bridge has existed for more than three centuries .   A. appeared      B. risen     C. said      D. born

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.   A. Remarkable                   B. Quite remarkably     C. It is remarkable that            D. It is remarkable   17. _____ you nominate will be elected.

A. Who        B. Which      C. Whomever     D. That’s  18. _____ book you borrow must be returned within a week.    A. What     B. Which     C. Whichever     D. That’s

19. _____ is troubling me is that I don’t have much experience in international commerce.

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

20. _____they wil go there to try another experiment has not been decided yet.

A. Whether   B. If      C. About whether     D. Why