Unless you work as hard as you can, you won’t ______ your classmates.
A.fall behind
B.keep on with
C.keep up with
D.catch up
网友回答
C解析本题考查动词短语辨义。句意: 如果你不尽可能的努力学习，你就跟不上你的同学。fall behind 落后；keep on不和with搭配；keep up with跟上……，不落后于；catch up跟上……；后接with后才可接宾语。