下列各组互为等电子体的是
A.N2O和CO2
B.O3和NO2
C.CH4和NH3
D.OH-和NH2-
答案:A
下列属于季风区和非季风去分界线的是( )
A.大兴安岭—阴山—贺兰山
B.昆仑山—阿尔金山—横断山
C.大兴安岭—太行山—巫山—雪峰山
D.秦岭—淮河
.
._____ the mud from your shoes before coming in, or you will make the floor dirty.
A.Removing
B.To remove
C.Removed
D.Remove