He started swimming when he was four years old.(改为同义句)

问题描述:

He started swimming when he was four years old.(改为同义句)

能不能给我一些词,就是你那个题目下面出现的词,让我知道该改成什么样,不然能改成太多种了~~He started swimming_______ _______ _______ ________ ________.应该是at the age of four