2.
在\(□\)\(ABCD\)中,\(AC\),\(BD\)交于点\(O\),过点\(O\)作直线\(EF\),\(GH\),分别交平行四边形的四条边于\(E\),\(F\),\(G\),\(H\)四点,连接\(EG\),\(GF\),\(FH\),\(HE\).
\((1)\)如图\(①\),试判断四边形\(EGFH\)的形状,并说明理由;
\((2)\)如图\(②\),当\(EF⊥GH\)时,四边形\(EGFH\)的形状是________;
\((3)\)如图\(③\),在\((2)\)的条件下,若\(AC=BD\),则四边形\(EGFH\)的形状是________;
\((4)\)如图\(④\),在\((3)\)的条件下,若\(AC⊥BD\),试判断四边形\(EGFH\)的形状,并说明理由.