单项选择题
The main function of the drawworks on a ship is to（）.
A.transport tubulars from the pipe racks to the derrick floor B.maintain constant tension on the marine riser C.store and secure the excess drill line D.lower and hoist the drill string into and out of the drilled hole
单项选择题 The joint formed when two steel plates are placed end-to-end is called a（）.
单项选择题 The inner bottom is the（）.
单项选择题 The flood stream here is at an average rate of 0.8（）.
