A. I love you, Mum.
B. What colour is it?
C. My favourite colour is green.
D. Thank you to my teachers!
E. What's your favourite song?
如图,在Rt△ABC中,∠C=90°,AB=2BC,则sinB的值为( )
1:10000000的地图,AB两地的图上距离为20厘米,AB两地的实地距离是( )
下列各图中,正确表示引发泥石流因子的是( )