（ ）is not the advantage of GERT （Graphical evaluation and review techniques）as compared with PERT （project evaluation and review techniques）.

A. Allowing looping

B. Allowing for dummy tasks

C. Allowing branching

D. Allowing multiple project end results

( )主要用于杆件基本形加工工序中。

A．磨床

B．刨削机械

C．雕刻机械

D．工作凳