A:It's a birthday cake.
B:It's black.
如图所示,⊙O中,OA⊥BC,垂足为H,∠AOB=50°,则圆周角∠ADC的度数是( )
The global financial crisis(金融危机) has made many people_____ their money.
Ⅲ、过直线上一点作这条直线的垂线;Ⅳ、作角的平分线.
如图是按上述要求排乱顺序的尺规作图:
则正确的配对是( )