My friend has returned from the UK.She ___ at Oxford for four years,during which we communicated with each other on the Internet.A.studied B.has studied C.had studied D.has been 为什么选A不选C?
问题描述：
My friend has returned from the UK.She ___ at Oxford for four years,during which we communicated with each other on the Internet.
A.studied B.has studied C.had studied D.has been 为什么选A不选C?
答
这里要用过去完成时，表示过去发生的事情，延续在过去
因为这里的翻译是：我们朋友已经从英国回来了，她在牛津学习了4年，这期间我们一直在网上联系
这里表示是过去持续学习了4年，所以是 C had studied
答
过去完成时与现在完成时二者用法基本相同，但现在完成时以现在的时间为基点，过去完成时则以过去的时间为基点，与现在无关，即过去的过去。
说话的时候（现在）我的朋友已经从UK.回来了。语境中的时间点是现在。她呆在Oxford四年只是过去的一个行为，所以选A.
还有也可以从后半句during which we communicated with each other on the Internet.中communicated来推断应该选studied 。
答
C选项为过去完成时,通常表达是“过去的过去”,切记这一点.比如,He said that he had finished his job.这里完成工作在‘说’的过去,所以用过去完成时.在过去的一段时间内做了某事,直接用过去时就行了.