George is going to talk about the geography of his country，but I’d rather he________more on its culture.
A：foucs
B：focused
C：would focus
D：had focused
二里头遗址的墓葬呈现出不同的埋葬方式，这说明死者生前( )
（Ⅰ）求m的最大值；
（Ⅱ）已知a＞0，b＞0，c＞0，且a+b+c=m，求4a2+9b2+c2的最小值及此时a，b，c的值．
我国改革开放的前沿地带是（ ）
