“must”在特殊疑问句中的用法及回答如下：
表示“必须”或“一定要”
肯定句：You must finish your homework today.
否定句：You needn't finish your homework today.
疑问句：Must I finish my homework today？
表示推测
肯定句：He must be at home now.
否定句：He can't be at home now.
疑问句：Must he be at home now？
用于反意疑问句
肯定句：You must study hard, mustn't you？
否定句：You needn't study hard, needn't you？
总结：
Must用于特殊疑问句时，主要询问对方是否有某种义务、必要性或推测某种情况。
肯定回答通常使用“must”。
否定回答可以使用“needn't”或“don't have to”。
希望这些信息对你有所帮助。
