①AB与BC被AD所截得的内错角有_____________;
②DE与AC被AD所截得的内错角有_____________;
③DE与AC被BC所截得的同位角有_____________;
④∠5、∠7是_____________被_____________直线所截得的_____________角;
⑤∠1、∠4是_____________被_____________所截得的_____________角;
⑥∠B、∠7是_____________被_____________所截得的_____________角.
(5)如图,直线AB、CD、EF两两相交,请指出∠1与其它有标号的角是什么角?