we must keep quiet when others answer question 改为祈使句

问题描述:

we must keep quiet when others answer question 改为祈使句
i think lily has to stay at home at night 改为否定句

1 Let's keep quiet when others answer question.
2 I don't think lily has to stay at home at night
加油!不明白再问!第一个空是 ____ ____  whenothersanswerquestion( Keep quiet ) when others answer question .