单项选择题
A.As long as
B.As far as
C.As well as
D.Unless
单项选择题 （）, we kept removing the pistons.
单项选择题 The value of GM still remains one meter, meanwhile we can pump the ballast water to（） the ship on even keel.
单项选择题 After the order “（）” is given, the air system is shut down, the turning gear put in, all drains and indicator cocks opened, and the cooling water and lubricating oil systems kept running.