在列管式换热器中,在一些腐蚀严重、温差较大而需经常更换管束的冷却器中应用较多的是()。
A.固定管板式换热器
B.U形管换热器
C.浮头式换热器
D.填料函式列管换热器
参考答案:D
点(2,-3)先向右平移2个单位,再向下平移3个单位,所得的点的坐标为______.
It’s believed ______40% of stars, like the sun, may have planets that orbit them.
A.as many as
B.as much as
C.many more
D.much more