常用的多模光纤的纤芯半径为()。
A.9μm
B.10μm
C.25μm
D.50μm
参考答案:C
— Could you tell me if Ann ____ to my birthday party tonight?
— I'm sure she will if she has nothing else to do. [ ]
A.came
B.was coming
C.comes
D.is coming
局域网的覆盖范围是()公里。
A.10公里以内
B.100公里以内
C.上千公里
D.上万公里