She felt anxious about her son as she ________ for quite a long time.A.haven't heard himB.hadn't heard himC.haven't heard from himD.hadn't heard from him
网友回答
D解析本题旨在考查谓语动词的时态。因为主句中的谓语动词是一般过去时，而从句中的动作发生在主句动作之前，所以应该用过去完成时态；“收到某人的来信”是固定搭配“hear from sb.”。