( )The little boy___swim across the river when he was ten.A.can B.would C.was able to D.will

题目

( )The little boy___swim across the river when he was ten.A.can B.would C.was able to D.will
( )The little boy___swim across the river when he was ten.
A.can B.would C.was able to D.will
正确答案是C,但请问为什么是C?还有,请大家说说,为什么不能选A?

答案

答案是对的.因为这里问题的主要意思是,那个小男孩在他十岁的时候就能够游过那条河.
这里是一种肯定,已经能够游过去,所以用will和would不合适,它们都表示将来.
这里是过去时态应该用could,所以A不能选,而C中was able to 就相当于could.