This method is only applicable to the case that the time point f of EF bisecting the area of quadrilateral ABCD is on AB,

If the time point f at which EF bisects the area of quadrilateral ABCD is not on AB (but on the other side), there is no solution.

Because the quadrilateral ABCD is an arbitrary quadrilateral and the situation is complicated, the method shown in the figure is one of them.

For more details, please refer to the quadrilateral area bisection method.

This drawing method can be used as a straight line, which passes through any point on the side of the quadrilateral and bisects the area of the quadrilateral.

And it can be proved that the straight line passing through the center of gravity of the quadrilateral does not necessarily bisect the area of the quadrilateral.

A straight line bisecting the quadrilateral region through the four vertices of the quadrilateral can be drawn according to the method in the figure.

It can be seen that these four straight lines do not intersect at one point (except for special quadrangles)

Therefore, it is not feasible to use the method of "connecting point E with the center of gravity" in this question.