问题
选择题
The boy tries hard _______ the other students. [ ]
A. doesn't fall over
B. don't for behind
C. not to fall behind
D. not fall behind
答案
答案：C
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The boy tries hard _______ the other students. [ ]
A. doesn't fall over
B. don't for behind
C. not to fall behind
D. not fall behind
答案：C