单选题What is the purpose of the intake/exhaust valves in a diesel engine? （）AThey regulate the combustion cycleBThey supply cooling waterCThey synchronize the ignition sparkDThey supply and regulate the lubricant flow
单选题
What is the purpose of the intake/exhaust valves in a diesel engine? （）
A
They regulate the combustion cycle
B
They supply cooling water
C
They synchronize the ignition spark
D
They supply and regulate the lubricant flow
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