下载APP
举一反三
【多选题】下面有关光缆成端端接的描述,正确的是()。
A.
制作光缆成端普遍采用的方法是熔接法
B.
所谓光纤拼接就是将两端光纤永久性的连接起来
C.
光纤端接与拼接不同，属非永久性的光纤互连，又称光纤活结
D.
光纤互连的光能量损耗比交连大
【单选题】Subways are underground trains, which usually operate 24 hours a day. They are found in larger cities and usually run between the suburbs and the downtown area. Maps and schedules are available from t...
A.
within downtown areas
B.
away from city centers
C.
in or outside big modern cities
D.
between suburbs and city centers