含有情态动词的被动语态,如何变成被动语态的一般疑问句?

含有情态动词的被动语态,如何变成被动语态的一般疑问句?
只要把情态动词调前就可以了.
The sentence can be translated this way.
Can the sentence be translated this way?
Your homework should be finished(by you) at once.
Should my homework be finished at once?-Yes,it should./ No,it shouldn‘t.
This work must be done at once.
Must this work be done at once?-Yes,it must./ No,it needn‘t.
回答应保留原情态动词,但must表"必须"时,其否定回答应用needn‘t,need表"必要"时,其肯定回答应用must.这和主动语态类似.不是把be动词提前吗？不是!是将情态动词提前。改成(一般)问句，是把第一个动词提前。