单项选择题
The function of the bypass valve on the self-contained breathing apparatus is to（）.
A.control the pressure of the oxygen as it enters the body
B.allow the wearer to manually give himself oxygen
C.release excess heat which would otherwise cause the bottle to explode
D.allow exhaled gases to pass outside the bottle
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相关考题
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单项选择题
The extension of the after part of the keel in a single-screw vessel upon which the stern post rests is called the（）.
A.boss
B.knuckle
C.skeg
D.strut -
单项选择题
The exhaust pipe must be gas tight throughout its entire length otherwise（）.
A.bilge water may enter the exhaust pipe
B.entry of air may cause vapor lock
C.carbon monoxide may enter the interior of the vessel
D.the joint gaskets may be blown -
单项选择题
The connected joints of pipe，usually made of three joints of pipe approximately 90 feet long，racked in the derrick when making a trip are called a（）.
A.string
B.stand
C.joint
D.standpipe
