柴油机冒黑烟的原因及排除方法?
参考答案:
柴油机冒黑烟的原因有:①柴油机超负荷工作,②进气不足。③气门间隙不正确,有漏气现象。
排除方法是:减转负荷;清洗空气滤芯;调整气门。
—Six-year-olds are not allowed to ride bikes in the street.
—I agree. They are _____ to ride bikes.[ ]
A.not old enough
B.too old
C.so calm
D. quite big
造成烟道阻力的增加有哪些原因?