乌金衣：

试论述教育与收入的关系。

—I am going to wear jeans to the party.

—If you do, the teachers ______ let you in. [ ]

A. don't

B. didn't

C. haven't

D. won't

观光农业资源

Dos是一个典型的单用户单任务操作系统。

圆筒除清筛主要由冲孔圆形筛筒、（）及吸风部分组成。