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
单项选择题 The C02 flooding system is actuated by a sequence of steps which are（）.
单项选择题 The bypass valve on a self-contained breathing device should be opened if（）.
单项选择题 The boat is stowed on the davit rather than on a cradle with which type of davit?（）
