FP5012型破碎机的主要部件为:传动单元、()、电控装置和上下机体等。
参考答案:破碎辊
Smoking does great harm to our health. ( ) is smoking allowed in public places.
A.In no time
B.At a time
C.At all times
D.At no time
椭圆的的离心率为()。
A.选项A
B.选项B
C.选项C
D.选项D