问题
选择题
What great trouble the boy _____his father to give up smoking!
A．had to persuade
B．had persuaded
C．had persuading
D．had persuade
答案
C
题目分析：句意：这个小男孩在说服他的父亲放弃吸烟是多么的困难。这里是短语have trouble in doing做某事有困难；这里省略了介词in；这里是感叹句，被感叹的词是名词trouble所以用what，根据句意故选C。
