问题
选择题
It was not a good idea to go skating. You __________your leg.
A．can break
B．could break
C．could have broken
D．could have been broken
答案
答案：C
本题关键为抓住题中提供的信息。“It was not a good idea'’表明动作发生于过去，情态动词后接动词完成式表明对过去动作的猜测。