工艺生产中,提高蒸汽加热器热负荷的有效方法是()。
A、提高工艺物料流量
B、增加传热面积
C、提高蒸汽管网压力
D、提高工艺物料压力
参考答案:C
All the classes in this school _________ 60 students though they are of different ages。
A.are consisted of
B.consist of
C.is made upof
D.make up of
A.I= ,从上向下
B.I= ,从上向下
C.I= ,从下向上
D.I= ,从下向上