在一般燃气调压系统中，紧急切断阀是什么用途的？

核电作为一种重要的清洁能源，在实现（）方面可发挥重要作用。

城市燃气供应系统通常用（）类调压器调节燃气压力.

Every deliberate act of wrongdoing by the master or any of the crew against the ship or cargo，without the authorization or privity of the Shipowner or his agent，is（）.

（）, or drum is used for hauling in or letting out the wires or ropes which will fasten the ship to the shore.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The （） is used for hauling in or letting out the wires or ropes.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

交流发电机过电压故障是因（）

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

逻辑运算符（AND、NOT、OR）的运算顺序是AND→OR→NOT。

燃气及燃具中国的燃气事业在近二十年来迅速发展，八十年代以发展人工煤气为主，九十年代液化石油气发展较快，进入二十一世纪将以天然气为主要发展方向。