— _____
— It's an apartment building.
A:What's your home?
B:Where's your house?
C:What kind of house do you live in?
D:Where's the home?
读“马六甲海峡”位置图,回答.
如图,圆O是△ABC的外接圆,∠A=68°,则∠OBC的大小是( )