问题
选择题
By the end of last week, she______in the west of China for two months helping the homeless children.
A．will stay
B．has stayed
C．would stay
D．had stayed
答案
答案：D
题目分析：根据时间状语By the end of last week到上周末为止，可知本句描述的是过去某时之前已经完成的动作，故用过去完成时态，选D。