问题
选择题
They were determined to carry out the plan at first, but then we ________ persuade them to change their minds.
A．would
B．could
C．were able to
D．had to
答案
答案：C
考查be able to用法。Be able to do sth表示经过努力做成某事。句意：起初他们决定执行那个计划，但是后来，我们说服了他们改变了主意。