单项选择题
A.fitted in each leg of the towing bridle B.generally located between the "fishplate" and the main towing hawser C.secured at the "H" bitts D.usually made of manila hawser
An instrument that maintains a continuous record of hum...
单项选择题An instrument that maintains a continuous record of humidity changes is called a（）.
A.thermometer B.barometer C.hygrograph D.thermograph
An instrument that indicates wind direction is known as...
单项选择题An instrument that indicates wind direction is known as a(n)（）.
A.weather vane，wind vane or wind sock B.hydrometer C.hygrometer D.sling psychrometer
All of the following steps are taken in starting a cent...
单项选择题All of the following steps are taken in starting a centrifugal pump，EXCEPT to（）.
A.set the relief valve B.check the lubrication system C.vent the pump casing D.open the pump suction and discharge valves
