主语从句练习

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

A. The estimate B. The estimated 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 he