用所给单词的适当形式完成句子。

1. It's _____  (fool) of him to believe the hoax.

2. According to his _____ (describe), the police caught the criminal two days after the murder,

3. Children like stories with happy _____ (end).

4. Lots of  _____ (leaf) on the tree have fallen into the river nearby.

5. I was in the _____ (embarrass) position of having completely forgotten her name.

（2006）若平面力系不平衡，则其最后简化结果为：（）

A.一定是一合力

B.一定是一合力偶

C.或一合力，或一合力偶

D.-定是一合力与一合力偶