Its mean that if i wirte this code, so if the progrem did 60 frame in a half of a second(for example right, real its take 16 ms)so the rest of the second that mean another half of a second he will "sleep"? thats mean he have to do 60 frame and after he did that he can "Sleep" all the rest of the second that left him? am i right?

No that understanding of how Display.sync() works is incorrect, the 60 frames will not display as quickly as possible, instead it will take about 16ms to draw
each frame (i.e. time it actually took to draw the the frame + sleeping to make it a total of about 16ms) therefore it will take a full second to draw 60 frames.