A.4~8hB.8~24hC.24~36hD.36~48h
A.前者復(fù)雜,后者簡(jiǎn)單B.前者簡(jiǎn)單,后者復(fù)雜C.兩者均復(fù)雜D.兩者均簡(jiǎn)單
A.平臺(tái)B.限位塊C.下止點(diǎn)D.上止點(diǎn)