高中英语反义疑问句These trees must have been planted three years ago,____?A.weren't they B.mustn't they C.didn't they D.haven't they为什么不选D?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/10 07:30:08

高中英语反义疑问句These trees must have been planted three years ago,____?A.weren't they B.mustn't they C.didn't they D.haven't they为什么不选D?
高中英语反义疑问句
These trees must have been planted three years ago,____?
A.weren't they B.mustn't they C.didn't they D.haven't they
为什么不选D?

高中英语反义疑问句These trees must have been planted three years ago,____?A.weren't they B.mustn't they C.didn't they D.haven't they为什么不选D?
答案是C.
must have done 是对发生在过去时间段事情的推测,从句中three years ago也可以看出这一点.因此,反问时,要用过去时.即:These trees were planted three years ago.

选C,这些树肯定种于三年之前,ago表示过去,因此用过去式表示。

答案选C, 理由同 “朵朵可爱特别多”,
不选D, 因为只有助动词have 表示完成时态时,用have来构成反义疑问句,这个句子不表示完成时态,而是用 情态动词+have done 表示对过去的肯定的推测