Tom must be at home,(isn't) he? Tom must study at home,(doesn't) he? Tom must stay at home,(mustn't) he? 这三个句子中must后面的都是动词,为什么反意疑问时be 用isn't而不是其他两个的用法? 怎么判断是表示推测还是表示必须?
1Tom must be at home,(isn't) he? 此处,(isn't) he? 是对be at home提问,所以要用be提问 2Tom must study at home,(doesn't) he? 此处,(doesn't) he?是对study提问,所以要用do/does提问 3Tom must stay at home,(mustn't) he? 一般句子不用mustn't作反意疑问句提问