1.
否定句：We mustn't keep the library quiet.
一般疑问句：Must we keep the library quiet?
对划括号的提问：What must we do?
2.
否定句：He doesn't want to drink some water.
一般疑问句：Does he want to drink any water?
对划括号的提问：What does he want to drink?
3.
否定句：Tom didn't dust the cupboard at home this morning.
一般疑问句：Did Tom dust the cupboard at home this morning?
对划括号的提问：When did Tom dust the cupboard at home?