Verb conjugation of "thresh" in English

Yes, I speak a little bit of English. I'm just beginning to take English courses in private evening classes. Is your Spanish good? I will speak to you in Spanish and you teach me in English.
Please explain me the exact differences between British and American .... This year I'm trying to make the TOEFL. We can then discuss how we can prepare for this exam. I failed the first time.
I teach at the university of natural sciences. I have studied at the ETH in Zurich. At that time I started learning Spanish and I found Vocabulix. Since then I'm using it regularly with joy.