Complete the text with: for, since, just, already, yet.We designed several towers for a German bank in 2003, and we have

We designed several towers for a German bank in 2003, and we have designed about ten towers for them. In fact we have just 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 yet.  We haven\'t started the walls for tower yet, but we have already prepared the ground, and that\'s the most important part of the building. Since I started at Stockholms, I have learnt that preparation is everything.