A:hotter
B:hottest
C:colder
D:coldest
don't , Do , are , doesn't , is
关于港澳与内地联系的叙述正确的是
I couldn't play badminton and volleyball before.____
如图,OA是北偏东30°方向的一条射线,若射线OB与射线OA垂直,则OB的方位角是( )