英语：must 的反意疑问句怎么做啊？

看must后的谓语动词，be动词，就用相应的am，is 或are来进行反义疑问，如果是have那么可以用have或has或did或do来进行反义疑问。

陈述部分有must 的疑问句，疑问部分根据实际情况而定。
He must be a doctor, isn't he?
You must have studied English for three years, haven't you? / didn't you?
He must have finished it yesterday, didn't he?

含有must的句子的反意疑问句,需根据must 的意思去完成.当must 表示"必须''时,疑问部分用must; 当must表示"一定''时,疑问部分用 不用must,根据陈述句的谓语部分的结构选择疑问部分中主语之前的那个词.
举例如下;
1. You must be hungry,aren't you ?
2.They must finish their homework today,mustn't they?
3.The man musn't be our Chinese teacher,is he?

这要看情况而定.
1. must表示"必须",根据语气不同用needn't/mustn't来变化.
如: I must go now, needn't/mustn't I?
2. mustn't作“不允许”解释时,根据语气轻重用must/may来变化.
如: We mustn't be late, must/may we?
3. 如果must表示"一定,必定"即表示非常肯定的猜测时,则要去掉must,考虑句子的本来时态和谓语构成,进行相应变化
主要分以下三种情况:
1) must+动词原形(即对一般或现在的情况进行猜测),直接考虑该动词的构成并加以变化.