（） of an engine crankshaft can be detected by measuring deflections of crank webs for each unit of the engine.

A.Hot bearing 
B.Starting valves
C.Unequal distribution of load
D.Excessive crankshaft clearance

A.The fuel oil
B.The lube oil
C.The sea water
D.The fresh water

A.Gas exchange
B.Charging
C.Scavenging
D.Supercharging