题目：
A diesel engine could fail to start because of （）
A.incorrect injection timing
B.low exhaust back pressure
C.floating exhaust valves
D.excessive cranking speed
答案：
参考答案：A
A diesel engine could fail to start because of （）
A.incorrect injection timing
B.low exhaust back pressure
C.floating exhaust valves
D.excessive cranking speed
参考答案：A
