如果g某气体中含有的分子数为，则g该气体在标准状况下占有的体积应表示为（式中为阿伏加德罗常数）                                               

A．

B．

C．

D．

In software engineering and systems engineering, （）is a description of a system's behavior as it responds to a request that originates from outside of that system.

A.black box

B.busines srule

C.traceability matrix

D.use case