I am glad you have come back from Beijing.Please tell me how long you ____ there.
问题描述：
I am glad you have come back from Beijing.Please tell me how long you ____ there.
A)have stayed
B)had stayed
C)have been staying
D)stayed
请说明原因,
答
A为什么呢?have stayed表示层级在那里呆过，到现在仍然是存在的，没有终止的一个问题，所以用have不用had，用现在完成时，选项Chave been staying 不适合，因为已经回来了，而且stay for some time是不可持续动词，只是表示一种状态而不是动作。Dstayed表示过去式，很明显不适合，因为题目中要求的是意思是曾经呆过多久，用完成式。