什么是换热器?其主要有叫几种型式?
参考答案:
工业上实现热量佼换的设备统称为换热器,一般可分为:螺管式,套管式,夹套式,喷淋式,螺旋板式,板翅式,翅片管式。
—It's time for CCTV News. Please _____ the TV for me.
—Yes, Mom. [ ]
A. turn off
B. turn on
C. turn down
D. turn up
--___ you got to know my telephone number? ---Through a friend of yours.
A.How was it
B.How was it that
C.Was it how that
D.How did