用所给单词的适当形式填空。
1. Don't spend much energy _____ (make) others happy.
2. Why do many parents keep their children from _____ (go) out after school ?
3. It's necessary _____ ( keep) our classroom tidy and clean.
4. He pretended _____ (is) friendly with me. .
5. I thanked them for their _____ ( kind) they showed me.