--These days I can only sleep for four or five hours at night as I’m too busy with my research work.
--If you keep going on like that, you are sure to sooner or later.
A. break down
B. get down
C. calm down
D. put down
网友回答
(答案→)A. break down
B. get down
C. calm down
D. put down
解析：考查短语辨析。“现在，我只能睡四五个小时，因为我忙于我的研究工作。”“如果你继续那样的话，你一定早晚会垮掉的。”A“（身体）垮掉，分解，出毛病”；B“使沮丧”；C“平静下来”；D“写下，镇压”。故选A。