一、用括号内所给单词的适当形式填空
1. The sun is a ______ (power) source of energy for our planet.
2. Scientists have put forward several ______ (theory) to explain the origin of the universe.
3. ______ (general) speaking, students find it easier to learn when the material is presented in an interesting way.
4. It is ______ (know) that eating fruit and vegetables regularly can improve one’s health.
5. In the depths of the forest, there are ______ (hide) streams that provide water to the surrounding wildlife.

1. powerful 2. theories 3. Generally 4. known 5. hidden

1. —Now many people smoke and get ill.
—So we should do something ______ can help stop smoking.

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

B

2. —Qian Xuesen ______ the father of China’s space technology.
—Right! He is the real hero that we should respect.

A.is known as
B.is known for
C.is known to
D.is known at

A

3. —I’m not sure ______ Lisa can come to my party or not. ______ she can come, please let me know.
—OK.

A.if；If
B.that；Whether
C.whether；If
D.if；Whether

C