She ______swim when she was five years old

问题描述:

She ______swim when she was five years old
A.was B.can C.could

首先,she was five years old用的是过去时,而when 表示的意思是:在.的时候.所以前后时态一致,B就被否了.然而通读下来,句子所要表达的意思是:她5岁时就能游泳了.所以选C