磷化氢通常产生于一些厌氧体系。
参考答案:对
在网络计划中,工作N最迟完成时间为第25天,其持续时间为6天,该工作有三项紧前工作,它们的最早完成时间分别为第10天、12天、13天,则工作N的总时差为( )天。
A.6
B.9
C.12
D.15
—How was the televised debate last night?
—Super!Rarely so much media attention.
A.a debate attracted
B.did a debate attract
C.a debate did attract
D.attracted a debate