单项选择题
Piston No2 of main engine has been removed, and it will be （） by noon tomorrow.
A.lifted B.reassembled C.dismounted D.disassembled
单项选择题 Persistent knocking in one cylinder of a diesel engine could be caused by（）.
单项选择题 Operating conditions in the crank chamber are very （） those in the cylinder.
单项选择题 Opening of the cylinder （） will admit compressed air into the cylinder.
