Complete the text with: for, since, just, already, yet.
We designed several towers for a German bank in 2003, and we have designed about ten towers ... then. In fact we have ... finished the second of the three Stadmanton Towers. They opened the building this morning. I love towers, but I am a bit of nervous about Tower. Nobody has built a 400-metre tower .... We haven't started the walls for tower ... , but we have .... prepared the ground, and that's the most important part of the building. ... I started at Stockholms, I have learnt that preparation is everything.