---Mark broke his leg when he was playing football.---_____was that?A.since when B.since when ago C.how long ago C.
问题描述：
---Mark broke his leg when he was playing football.
---_____was that?
A.since when B.since when ago C.how long ago
C.
答
1、首先你要理解题目中的“that”是什么意思，指什么。它指Mark broke his leg 一事。理解了这一点，你就不难发现下句其实是对上文when he was playing football这一时间的划线部分提问。
2、如楼所言，since when作为疑问词是不存在的。
答
1AB的用法不对,since when 本身就是语法错误了,不可以用2how long ago was that那是多久以前了?i wonder how long ago this school was built我想知道这学校多久以前建造的?加个age就是表示强调多久以前做什么事因为...