用所给单词的适当形式填空。
1. _____ (eat) healthily is important for everyone.
2. She always does her best    ___   (study) every subject at school.
3. He wants to have a      ___ (health) life.
4. The boy used to behave ___ _   (bad) in class.
5. When he saw a book on the ground, he stopped _  ___ (pick) it up.