A.交通擁擠 B.建筑技術(shù)進(jìn)步 C.城市規(guī)劃改變 D.自然環(huán)境惡化
A.40% B.50% C.60% D.67%
A.有效經(jīng)過(guò)年數(shù)等于實(shí)際經(jīng)過(guò)年數(shù) B.有效經(jīng)過(guò)年數(shù)短于實(shí)際經(jīng)過(guò)年數(shù) C.有效經(jīng)過(guò)年數(shù)長(zhǎng)于實(shí)際經(jīng)過(guò)年數(shù) D.有效經(jīng)過(guò)年數(shù)可能長(zhǎng)于或短于實(shí)際經(jīng)過(guò)年數(shù)