以下属于电子媒介沟通渠道的是()。
A.电话
B.传真
C.电子邮件
D.通讯软件
参考答案:A, B, C, D
If you had done as I told you, this______.
A.should have not happened
B.would not have happened
C.did not happen
D.had not happened
铣床在进行周铣切削加工时,进给方向与切削力F的水平分力F。方向相同称为逆铣。