问题
选择题
Mr. Smith, I should tell you this is the fifth time you ______ me for my twin sister.
A．have mistaken
B．are mistaking
C．mistook
D．are mistaken
答案
答案：A
题目分析：句意：史密斯先生，我应该告诉你这是你第五次把我误认为是我的孪生妹妹。根据前面的this is the fifth time可知，后面用现在完成时。故选A。