适用于向缺隙方向倾斜基牙的卡环是()
A.Ⅰ型卡环
B.Ⅱ型卡环
C.Ⅲ型卡环
D.A和B均可
E.A和C均可
参考答案:B
— I'm leaving tomorrow.
— Oh, what a pity! I won't be able to see you off. I ____ a tele-conference the whole morning.
A.have
B.am having
C.will be having
D.will have had
在等距数列中,组距的大小与组数的多少成反比。