问题补充:
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
答案:
A. fall behind
B. keep on with
(答案→)C. keep up with
D. catch up
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。