22. There is a known problem. If the quadrilateral ABCD is a parallelogram and BE=DF, the conclusion can be proved.

The quantitative relationship of (1) is: AE = CF

The positional relationship is: AE parallel CF

Proof: Because the quadrilateral ABCD is a parallelogram.

So OA=OC= 1/2AC.

OB=OD

Because OB=BE+OE

OD=OF+DF

BE=DF

So OE=OF= 1/2EF.

AC and EF are equally divided.

So the quadrilateral AECF is a parallelogram.

So AE=CF

AE parallel CF

(2) Proof: Because the quadrilateral AECF is a parallelogram.

AC=EF

The quadrilateral AECF is a rectangle.