如图，∠AOB是⊙O的圆心角，∠AOB=80°，则弧AB所对圆周角∠ACB的度数是（ ）

⑴Where are your parents?____                           A. Yes, I'd like some fruit.

⑵Is your brother sleeping in the room?____      B. They are at home. 

⑶Can I help you?____                                         C. She's playing the piano.

⑷Would you like some fruit?____                       D. No, I'm not.

⑸Can you see the red light?____                        E. She's singing.

⑹What is Helen doing?____                                F. Yes, please.

⑺Are you busy?____                                           G. No, I can't.

⑻What is she doing in the music room?____     H. No, he isn't.

读南极地区图，完成问题．
 
关于我国四个南极考察站的叙述，正确的是（ ）