单项选择题
A.(1)+(2)
B.(1)+(3)
C.(2)+(3)
D.(1)+(2)+(3)
单项选择题 Excessive clearances in the main or crank-pin bearings will sometimes be indicated by （） before any bearing knock is heard.
单项选择题 Engine fuel pump index is （）.
单项选择题 Engine （） refers to the relative time of position of crank, at which each operation during the cycle is commenced and is completed.