普拉那气息是自然（）的。
A.上行
B.下行
C.向左
D.向右
参考答案：A
刃倾角是主切削刃在切削平面内的投影与（）之间的夹角。
A、前刀面
B、基面
C、切削平面
D、后刀面
Nowadays sending emails to each other is a way many a student ________ what they think.[ ]
A. conveys
B. convey
C. account
D. accounts
mails to each other is a way many a student ________ what they think.[ ]