A:砍伐森林.开垦草原,开发新的耕地
B:捕捉珍稀野生动物,进行人工饲养
C:积极围湖造田种粮,增产粮食
D:跨流域调水,改变水资源的地区分布不平衡状况
As teenagers, we're old enough ________ with housework. We can help set the table, wash the dishes and clean our own rooms.
①f(0)=0;
②若f(x)在0,+∞)上有最小值﹣1,则f(x)在(﹣∞,0上有最大值1;
③若f(x)在1,+∞)上为增函数,则f(x)在(﹣∞,﹣1上为减函数.
其中正确的个数是( )