Theyweredoinghomeworkwhenthetelephone

問題詳情：

They were doing homework when the telephone _______.

A. rings           B. was ringing         C. rang             D. has rang

【回答】

C

解析：when the telephone…是做作業的背景，所以用一般過去時。

知識點：動詞時態

題型：選擇題