天津市常被人们称为“河海码头”，这里的“河”和“海”分别是[ ]
A．黄河、黄海
B．海河、渤海
C．淮河、渤海
D．淮河、东海
答案：B
The method of constructing a project schedule network diagram that represents activities and connects then to show the all dependencies is known as （）.
A．precedence diagramming method
B．activity list
C．arrow diagramming method
D．schedule network templates
缸套的形式分为（）。
A.合金套
B.干式套
C.干湿套
D.湿式套
E.铸铁套
