问题
选择题
We must study hard ________ our English. [ ]
A. to improve
B. improving
C. improved
D. improve
答案
答案：A
搜题请搜索小程序“爱下问搜题”
We must study hard ________ our English. [ ]
A. to improve
B. improving
C. improved
D. improve
答案：A