-- Why are you so excited?
-- Peter invited me on a trip to Yuntai Mountain.
A:to go
B:go
C:going
D:went
已知AC⊥BC于C,BC=a,CA=b,AB=c,下列图形中⊙O与△ABC的某两条边或三边所在的直线相切,则⊙O的半径为aba+b的是( )
下面漫画给我们的启示是( )