—Look! The telephone is broken. Someone damaged it purpose.—That may be right. But perhaps it

—Look! The telephone is broken. Someone damaged it       purpose.

—That may be right. But perhaps it was broken       accident

A.on; by

B.by; by

C.on; on

D.by; on

答案及解析： A

解析：

本题考查介词。on purpose“故意地”；

by accident“偶然地”。