A:He likes it.
B:He's hard working.
C:He's a keeper.
如图所示,已知OA⊥OB,OC⊥OD,则图中∠1和∠2的关系是( )
如图,四边形ABCD是正方形,点E在直线BC上,连接AE.将△ABE沿AE所在直线折叠,点B的对应点是点B′,连接AB′并延长交直线DC于点F.