位于我国地势第一级阶梯上的山脉是( )
A:阿尔泰山
B:天山
C:秦岭
D:昆仑山
读某地地质剖面示意图,回答下列问题.
A____、B____、C____、D____、E____、F____、G____、H____、I____。
Houses in China's big cities are so unreasonably expensive that generally young couples can't afford _______ without their parents' financial support.