6. We cannot decide　　　　　　　 　(谁)should open the presen first　 .

5. In a few　 y　　　　　　 　time, those mountains will be covered with trees.

4.It is　 impossible　 for fish to live w　　　　　　　 　water.

3.The　 t　　　　　　　 　mother got into the lifeboat and joined her children.

2. They kicked a goal, but we s　　　　　　　 　got one ourselves　 .

1.A pet can help a person feel　 less　 l　　　　　　 .

10.Thank you for asking　 me to your birthday 　　　　　　　　　(聚会).

第(12)组：

9.This　 maths problem isn’t 　　　　　　　　(难) . I’m sure you can work it out easily .

8. We are students. It is our 　　　　　　　　(责任) study　 hard.

7.He didn’t feel well, and he played very badly during the　　　　　　　　 　(比赛) .