Hi Zewu from Sweden, welcome to the forums,
Actually, if you want to select your university you have to limit yourself to one thing that you like the most. Generally, American universities are a bit ahead of their Euroupean counterparts, that's because the theories usually are born and developed bu the linguists who teach there. You can have a look at the renown professors or teachers to say what's the school and interests of that department. For example, Chomsky is a main figure at MIT, so they focus more on generative grammar, and philosophy as mentioned here earlier. Sag is teaching at Stanford, so I guess HPSG is prominent. Edinburugh along with a German university that I do not remember its name are famous for computtional linguistics. There were lots of researches done by German linguistics on linking the Indo-Euroupean languages before, I'm not sure about now. And lots of work on isolated languages were done in the US decades ago, most probably there are some remaining from that tradition. And you can leave your question to be answered by a linguist here: [link]
As you'll see on the link, there are other useful information can be found there. Have a lookk at this, for example:
[link]
Good luck with your studies,