题目

My father walked _____ in the room, looking as if he was thinking over something. A. now and then       B. up and down C. again and again      D. over and over 答案：B 解析: now and then表示时间；again and again和over and over表示次数。这三个短语都不符合语境。walk up and down in the room意思是“在房间里踱来踱去”。

查看本题答案和解析