when did you start to play tennis?A.when I was ten b.since two years ago为什么
问题描述：
when did you start to play tennis?A.when I was ten b.since two years ago为什么
答
A. when did you start 是过去式，since与完成时连用。
祝你学习进步，更上一层楼！ (*^__^*)
不明白的再问哟，请及时采纳，多谢！
答
A.when I was ten 当我10岁时,用过去时
B.since two years ago 自从2年前以来,用现在完成时
所以选A