A：O2
B：CH4
C：CO2
D：H2S
能直观表现区域内地面起伏和坡度陡缓的地图是
（Ⅰ）讨论函数f（x）的单调性；
（Ⅱ）若函数f（x）有两个相异零点x1，x2，求证x1x2+4＞2（x1+x2）+e（其中e为自然对数的底数）
Workers built shelters for s____ whose homes had been destroyed.
— No, I went there ________.
