单项选择题
A.the inlet valve is open
B.the exhaust valve is open
C.both valves are close
D.both valves are open
单项选择题 The outside diameter of the pipe is （） the diameter of the bore of the piston rod, the result being that an annular space formed between the piston rod and the pipe.
单项选择题 The outside diameter of the pipe is （） the diameter of the bore of the piston rod, the result being that an annular space formed between the piston rod and the pipe.
单项选择题 The operation between two fuel injections is called a working cycle, which consists of a fixed sequence of eventsWhat does "which" mean in this sentence?（）