如图,已知AB=AC=BD,那么∠1和∠2之间的关系是( )
A:∠1=2∠2
B:2∠1﹣∠2=180°
C:∠1+3∠2=180°
D:3∠1﹣∠2=180°
His failure made his father think him a ___________ boy.
唐太宗的治国政策有哪些?