下列不属于生态系统的是[ ]
A．大沟河水库
B．博爱农场的一群奶牛
C．良安蔬菜基地
D．王屋山国家地质森林公园
答案：B
16．In no place of China_______little about the economic development nowadays.
A．the local government cares
B．does the local government care
C．doesn't the local government care
D．cares the local government
（）适用凸模或较浅的型腔三维曲面工件的粗铣加工。
A.垂直插铣
B.等高层铣
C.平行加工
D.仿行加工
