A:土地沙漠化
B:湿地锐减
C:全球气候变暖
D:水土流失
将两个顶点在抛物线y2=2pxp>0上,另一个顶点2p,0,这样的正三角形有( )
下面能正确表示人体肺循环途径的是( )
It is generally considered unwise to give a child he or she wants.