在线路或设备上安装有防止触电的速断保护装置情况下，应选用满电动动作电流为（）的漏电保护器。
A、10mA
B、30mA
C、1A
D、50Ma
参考答案：B
Harvard, ________ in 1636, is one of the most famous universities in the USA.[ ]
A. which is set up
B. which is built
C. which was
D. which was
非承运人原因造成的航班延误包括（）。
A.空中交通管制
B.油料保障
C.飞机清洁
D.机场设施
