单项选择题
A.the pressure of the starting air is high enough
B.there is enough air in the air reservoirs
C.the air is supplied into the cylinders in the appropriate sequence
D.all of the above
单项选择题 “The engine not obtaining the sufficient speed for firing” means that （）.
单项选择题 The engine may lose power or slow down during running, when this occurs, the first cause possible may be hot bearings and （） of the pistons in the cylinders.
单项选择题 The engine is started with （） supplied from air receivers.