must,need,引导的疑问句回答方式有什么不同?

must,need,引导的疑问句回答方式有什么不同?
must,need,引导的疑问句回答方式有什么不同?

must,need,引导的疑问句回答方式有什么不同?
Must I go off now
Yes,you must.
No ,you needn't/don't have to.(否定形式mustn't是禁止、不许,所以不用)
Need I gave him a hand
Yes,you must/should.（ 情态动词need不用于肯定句中）
No,you needn't.