Roland Johansen
Deity
Can you pre build wonders like you could in Civ3?
Not really. You can't switch production from one item to another and take the production invested in one item and invest it in another. Hammers invested in one building or unit remain with that building or unit and aren't magically transferred to another. But they aren't lost either when you do switch production to something else. They remain invested in the original item making this item partially finished.
Since production overflows from one item to the next, you can get some production overflow from the previous construction into a World Wonder. However, this overflow is also limited and will generally not help you finish a World Wonder a lot quicker.
Simple example of production overflow: You're presently building a library at 20 hammers per turn and it's at 80/90 hammers. Next turn, it will be finished and your next construction project will start at 10 hammers.