(2)DG/OC=AD/AO，DG=4-2m

BE/BO=EF/OC，BE=8-4m，OE=OB-BE=8-(8-4m)=4m，DE=OE+OD=4m+m=5m，

S rectangle dgfe = de * DG = 5m * (4-2m) = 20m-10m? ; 0 & ltm & lt2

(3) The vertical line from point M is called the X axis of point H, FM = 2/5dF, FM/DF = 2/5, DF/DM = 5/7 = EF/MH, and MH = 7 (4-2m)/5.

DE/DH=EF/MH，5m/DH=(4-2m)/7/5(4-2m)，DH=7M，0H=6m

Then the coordinate of point M is (-6m, (-28+ 14m)/5), and the balance is not equal to 0, so point M is not on a parabola.