根据句意，用括号内所给的单词的适当形式填空。

1. It’s getting warmer and warmer, and some students feel        in class.(sleep)

2. He did his homework so ______ that he made a lot of mistakes. (care)

3. The players washed their uniforms          (they).

4. He’d like to buy a present for his father’s ______ (forty) birthday.