According to the meaning of the question, after sticking a small counterweight with the mass of m 1 on the disk diameter AE near the point A, the center of gravity of the moment disk is corrected to the center of the disk; The correction effect can also be achieved by digging a small hole with the mass of m2 on AE near point E (that is, the position symmetrical to the small counterweight).

It shows that after a small hole with a mass of m2 is dug near point E on AE, the center of gravity of the rest is at point O.. It also shows that the center of gravity of m 1 and m2 is at point O, so according to the moment balance condition, there are:

m 1gl=m2gl

So m 1=m2.

When A, B, C and the turntable are in different positions, the gravity moment is different, so A is wrong, B is wrong, and C is wrong;

D, hang a suitable hook code somewhere in the AE line segment to balance the torque disk, and the center of gravity of the torque disk and hook code is at the O point, so D is correct;

So the answer is: OE; =; D.