问题 多项选择题

设备加电前应检查哪些参数:()。

A.供电回路相互和对地均无短路现象

B.接电联接牢固可靠

C.供电设备的输出开关断开且输出电压正常

D.额定输出电流满足受电设备需求

E.受电设备全部电源开关断开

答案

参考答案:A, B, C, D, E, F

选择题
阅读理解

Manhattan Island is surrounded on the east by the East and Harlem Rivers and on the west by the North and Hudson Rivers.It links with the other four towns which make up New York City and with New Jersey are by means of subways,underground tunnels and bridges which lead into Manhanttan from the surrounding area.

The Brooklyn Bridge was the first suspension bridge to link Brooklyn to Manhanttan.It is also the second oldest bridge in New York.The architect was John Augustus Roebling,who was the chief engineer of the suspended Railroad Bridge at Niagara Falls.

Misfortune accompanied the building of the bridge,which took place from 1869 to 1883.The architect died as a result of an accident early during the construction.His son,Washington Roebling,carried on his father’s work,using the most advanced engineering techniques of the day.He also fell ill during the construction of the bridge and was obliged to direct the work on it from an apartment window overlooking the site.

Since its construction the Brooklyn Bridge has remained a busy and important passage in New York.

The Brooklyn Bridge is 6775 feet long and 1595 feet wide.The suspended part is 3450 feet long and 85 feet wide.It has a clearance of 133 feet above water level.Four huge cables extend across the bridge,supported by two towers,each 272 feet high.Each of these cables is made up of 5700 wires.

小题1:If you want to go to Princeton University in New Jersey from Manhattan,you_________.

A.must drive across a bridge

B.must take a Metro train

C.have to go through a tunnel

D.can use any of the above means小题2:The Brooklyn Bridge is _________.

A.the first suspended railway bridge in the USA

B.the first oldest bridge in New York

C.the first suspension bridge between Manhattan Island and Brooklyn

D.the first suspension bridge built in the USA小题3:In the course of the construction of the bridge_________.

A.the chief engineer was in short of money

B.misfortune fell on the chief engineer

C.John Augustus Roebling fell ill

D.Washington Roebling met with an accident小题4:Washington Roebling was forced to_________.

A.direct the building work on the bridge

B.lead the builders of the bridge in a hospital

C.give his directions to the workers from a flat nearby

D.direct the construction of the bridge by radio