用所给单词的适当形式填空

1. Trees must __________(prevent) from being cut down.

2. They __________(plant) ten thousand trees by last spring.

3. The sheep __________(tie) to the tree has eaten a lot of grass.

4. I can easily hear combs __________(go) through hair.

5. Great changes __________(take) in our hometown in the last ten years.

根据九分法，成人两上肢占人体体表总面积的

A．25%

B．35%

C．18%

D．30%

E．20%