A:过度的迁移农业
B:商业性伐木
C:雨林光合作用强烈,生物循环过于旺盛
D:开辟大型农牧场
When you see a fire,quickly go outside,never stop for toys or clothes.
He turned from side to side, eyeing himself in the mirror with a serious, studied ______ that soon changed into a smile.
设双曲线x2a2-y2b2=1a>0,b>0的离心率为e=2,右焦点为F(c,0),方程ax2-bx-c=0的两个实根分别为x1和x2,则点P(x1,x2)( )
掌握一定的技术能更好地服务生活,下列做法不可行的是( )