I don't think your sister has finished her course,__?A.do I B.hasn't she ..I don't think your sister has finished her course,__?A.do I B.hasn't she 为什么不选A,请详解

I don't think your sister has finished her course,__?A.do I B.hasn't she ..I don't think your sister has finished her course,__?A.do I B.hasn't she 为什么不选A,请详解
I don't think your sister has finished her course,__?A.do I B.hasn't she ..
I don't think your sister has finished her course,__?
A.do I B.hasn't she 为什么不选A,请详解

I don't think your sister has finished her course,__?A.do I B.hasn't she ..I don't think your sister has finished her course,__?A.do I B.hasn't she 为什么不选A,请详解
这题答案应该是has she?不是hasn't
主句用第一人称+think表达自己的想法意见,此时不对主句进行反义疑问,即,I think没意义,可以拿掉,但是注意not要保留,所以此句是前否后肯.

当前面有i think ，i believe等的时候，主语要看后面的believe、think所指的对象， 所以谓语就说的后面的对象对应的has，我认为你妹妹没有完成她的作业，不是吗？是对后面妹妹的反问，故应用hasn‘t

当陈述部分是I think 加从句时，疑问句应和从句的人称时态保持一致
A：我不认为你sister已经完成课程，我这么认为吗？
B：我不认为你sister已经完成课程，她完成了吗？
以上翻译，明显A说不通啊。。

这是一句对话，甲对乙说：“我不认为你的姐（妹）完成了她的课程。”
A答案填进去就是“我有吗？”B答案正解，意思为“她没有吗？”表示疑问。主语要搞清楚哟，还有对话的情景。