问题
选择题
I heard that some patients who had undergone laser eye surgery experienced sudden losses of vision, ______?
A．didn’t I
B．hadn’t they
C．didn’t they
D．isn’t it
答案
答案：C
考查反义疑问句。本题的I heard是插入语，后面句子的主语是some patients，是复数形式；谓语动词是experienced，是过去式；所以答案为C