根据句意及首字母的提示，补全单词。

1. He is 12 years old. He can make his own d          

2. When he was young, he got t_____ a hard time living in the countryside.

3. Please do your homework as c_____ as possible.

4. His parents said they would help him to change his a_____ to study.

5. She always feels s  ___  . She should go to see a doctor.

MEA脱除CO2是物理吸收法。