be able to和can的区别

题目

be able to和can的区别
I went there in 1984,and that was the only occasion when I ________ the journey in exactly two days.
A.must take                          
B.must have made
C.was able to make                    
D.could make
C D的区别?

答案

can 和be able to 都可以表示能力.can泛指一般的能力,而且只有两种形式,即:can,could．be able to 则主要指具体做到了某件事的能力,其形式主要是靠be 发生变化,所以形式比can 多．可以说：I can swim.I am able to s...