计算(x8)2÷(x2)3的结果是( )
A.x10
B.x8
C.x6
D.x12
答案:A
Keep on trying even when you are in trouble, ________?
A.will you
B.do you
C.shall you
D.can’t you
下列哪种设备不属于间壁式换热器?()
A.1-2型管壳式换热器
B.2-4型管壳式换热器
C.套管式换热器
D.回转式空气预热器