加工材料的硬度较低,楔角β一般取()。
A、5°~20°
B、20°~35°
C、35°~50°
D、50°~65°
参考答案:C
It's ten o'clock. Let's to bed.[ ]
A. go
B. to go
C. goes
D. going
--_______ do you usually go to work?
--I often ride a bike.
A.What
B.How
C.When
D.Where