根据下列句子的意思及所给的汉语、英语及首字母提示，写出空缺处词语的正确形式。

1. He was so sleepy that he could h________ keep his eyes open.

2. Tom is ________(thin) in his class.

3. All the ________(thief) have been caught.

4. I can't buy that book. I have ________(用完) my money.

5. My mother often ________(鼓励) me to be brave when I was very young.