什么叫简单冷凝？
参考答案：
空气的简单冷凝是指在密闭容器中定压下的冷凝过程。
Other businesses, such as insurance companies, are more concerned with acquiring a central position so that they are ______ to the urban population.
A．beneficial
B．relevant
C．independent
D．accessible
下图为两块钢板用拼接板连接，采用三面围焊缝，承受静力荷载作用。
焊脚尺寸应根据下列哪一项确定？（）
A.A
B.B
C.C
D.D
