在一定系统压力及组成下，液体混合物加热汽化全部变成饱和气相的温度为该液体混合物的露点。
参考答案：对
How should you signal the crane operator to raise the boom?（）.
A.Extend arm with the thumb pointing up and flex the fingers in and out
B.Place both fists in front of the body with the thumbs pointing upward
C.With forearm vertical and forefinger pointing up,move hand in small horizond circles
D.Extend arm with the fingers closed and thumb upward
集雨灌溉系统集水工程常用的材料都有哪些？
