A:①②
B:①④
C:②③
D:②④
如图,⊙O是△ABC的外接圆,∠B=60o,0P⊥AC于点P,OP=23,则⊙O的半径为( )
世界上最长的山脉是( )
Afterwards, we received a letter, in which he offered an a____ for his rudeness at the party.
如图,△ABC中,∠ACB=90°,沿CD折叠△CBD,使点B恰好落在AC边上的点E处,若∠A=25°,则∠BDC等于( )