问题
选择题
We must try our best _____ our English. [ ]
A. improve
B. improving
C. improved
D. to improve
答案
答案：D
搜题请搜索小程序“爱下问搜题”
We must try our best _____ our English. [ ]
A. improve
B. improving
C. improved
D. to improve
答案：D
；0)，其分布函数为F(x，y)，已知F(μ，y)=
，则y=______．