A.生產(chǎn)期B.投產(chǎn)期C.建設(shè)期D.經(jīng)濟(jì)壽命期
A.年終B.任意時(shí)間點(diǎn)C.年中D.年初
A.時(shí)間不同性B.隨機(jī)性C.復(fù)雜性D.經(jīng)濟(jì)性