G.654光纤/光缆的特点是什么?
参考答案:
G.654光纤/光缆为1550nm波长衰减最小单模光纤,一般多用于长距离海底光缆系统。
—May I put my coat here?
—No, you _______. If you do, you may lose it. [ ]
A. needn't
B. won't
C. wouldn't
D. mustn't