---May I use your cup Tom?---Sorry it by my sister just now. A.was broken B.is broken C

问题补充：

---May I use your cup, Tom?

---Sorry, it by my sister just now.

A.was broken B.is broken C.broke

答案：

解析：被动语态的用法。根据句意可知是被动语态，又时间状语为just now，故答案为A。