单项选择题
A.the later B.the latter C.the former D.the farmer
（）, the following possible causes should be investigate...
单项选择题（）, the following possible causes should be investigated.
A.Should the engine stop without apparent reason B.The engine should stop without apparent reason C.The engine stops without apparent reason D.The engine is stopped without apparent reason
We have planned to remove the piston with the help of a...
单项选择题We have planned to remove the piston with the help of assistant engineers during the cargo unloading, while the vessel （）port Shanghai.
A.reaches to B.gets C.calls on D.calls at
（）does it take to change the main engine from ahead to ...
单项选择题（）does it take to change the main engine from ahead to astern?
A.How many times B.How much water C.How long D.How length
