光纤通信的短波长传输窗口是()μm。
A.0.65
B.0.85
C.1.31
参考答案:B
Whenever you are in trouble ,don’t hesitate _____us for help.
A.in asking
B.with asking
C.to ask
D.to asking
所谓欧洲债券是指在外国发行销售,但并不以该国货币计值的债券。 ( )