“W”火焰的燃烧中心就在煤粉喷嘴出口附近，煤粉喷出后就直接受到（）的加热，从而提高了火焰根部的温度水平，对着火有利。
参考答案：回流高温烟气
— I ran into ______ back of ______ truck yesterday and damaged my car badly.
— I suppose you were driving too fast.[ ]
A. the; the
B. a; a
C. the; a
D. a; the
单转子液体连通器罗经的液体连通器产生（）。
A.摆性力矩
B.阻尼力矩
C.以上都不正确
