如图在⊙O中,弦AB=8,OC⊥AB,垂足为C,且OC=3,则⊙O的半径( )
A:5
B:10
C:8
D:6
(____)He wants to play baseball.
(____)Tim was so happy because he got a gift.
(____)Why are you wearing a Tshirt?
(____)I am going to the cinema tomorrow.
(____)It's difficult to fly a kite.
下列二次根式,不能与 12 合并的是____(填写序号即可).
① 48 ; ② -125 ; ③ 113 ; ④ 32 ; ⑤ 18 .