Verb conjugation of "sharpen" in English

I've met the owner of Dessarmile, who has also already written you (after you came back from Thailand). However, he does not speak Spanish and therefore I do not think that they can be good friends.
You have to be careful when you go on summer vacation. There are many dangers but the most dangerous one is the sun itself, because if you're not careful it may harm you. People underestimate the rays.
How are you? I want to meet you when you are in Austria? At the weekend I took the train home, and tomorrow I'm going back again to Karlsruhe in the south of our country. It is near Freiburg.