题目内容：

your room must have been cleaned yesterday,_____ it?答案是wasn't it 请明确回答谢谢

优质解答

做反义疑问句的时候 首先要搞清楚助动词是哪一个
例如You must have been playing tennis at the time,这句话中have做助动词 引导现在完成进行时 故应该是
You must have been playing tennis at the time ,haven't you
She must have a kind mother,这句话中must表示推测,而不是表“必须”,反意疑问句应该提取后面的助动词 have做的是实意动词 表示“有”的意思 其助动词应该是do
因为是第三人称单数 所以应该是She must have a kind mother,doesn't she?