什么叫空分装置分馏塔的精馏过程？
参考答案：
在定压下，多次的部分蒸发和部分冷凝过程的结合称为精馏过程。
IP地址占用_____个字节。
A．3
B．2
C．1
D．4
Bobbie is always sick and weak his brother Frank is a good football player, as strong as a horse.
A．when
B．as
C．while
D．though
