ok, i now KNOW the ways of population control. But i dont know HOW. like..

1. How do u sacrafice a population for production?

2. how do u do that one thing, i forgot what he called it, but it limited city growth (population)?

Please, please answer this. and just think, the answers could help other new civ players in need too ^_^

To answer your questions:

1. Implement the Slavery civic. Once you've done this, in the city display, the panel of buttons immediately to the right of where you choose what to produce has an icon that allows you to expend population for production.

2. That same panel has a number of other buttons. One of them gives the option to limit city growth. Just don't forget to turn it back on later, or your city will stay that way.

thanks man