The article written by the famous economist is really _______. None of us can understand it.
A:attractive
B:accessible
C:abstract
D:absolute
如图所示,从一点O出发引射线OA、OB、OC、OD,请你数一数图中有多少个角,并把它们表示出来.
Mr. Green will arrive here and give us a speech ___________ the morning of December 22nd.