Have you seen these tutorials? (sorry for the spaces in links, remove them after copy/paste)
Look at Timescaling step
https://www.scirra.com/ tutorials/ 67/ delta-time-and-framerate-independence
https://www.scirra.com/ tutorials/ 450/ timers
thanks your suggestion, but actually, i want to know how to make the whole game back in time, all things return back. for example, OBJ A takes player 3s to jump from Position B to Position C, then i press a button, A will back to C, and the time back in 0s.