当前，人类面临的共同问题是[ ]
A．水土流失、土地沙化
B．流行病的防治
C．资源的短缺
D．人口、资源、环境问题
答案：D
—Did your uncle tell you ________?
—Yes, he said he went there in 2008. [ ]
A. how he goes to Wuhan
B. why did he visit Kunming
C. when he traveled to Hong Kong
D. where did he spend his vacation
建筑物经济寿命与自然寿命的关系为( )。
A．经济寿命≤自然寿命B．经济寿命≥自然寿命C．经济寿命=自然寿命D．经济寿命＞自然寿命
