用所给词的适当形式填空。

1. Many great __________ (lead) worked together to fight for peace during the World War II.

2. He made a few friends in Shanghai when he __________(far) his studies there.

3. We don't allow __________ (make) noise in the library.

4. The guide __________ (铺开) his map on the ground and began to study it.

5. Our noses sometimes stop __________ (工作) when we have a cold.

6. Their star trips are full. But you can go to the moon. It's __________. (便宜)

7. He __________ (解释) why he came to school again just now, but none of us believed him.

8. The boy always__________ (尖叫) when someone plays with him with a plastic dinosaur.