— What courses are you going to do next semester? — I don't know. But it's about time ______ on something.[2002]
【正确答案】 B
【答案解析】解析：n is(about／high)time+从句，表示早该做而未做的事，是建议的意味，其动词形式用过去式。因此B项符合要求。