Verb conjugation of "erwerben" in German

The current situation in Libya is really difficult. I tried to get in contact with acquaintances, but all the phones were not working. I'm really concerned about their well-being. I'll try again later.
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'm still doing many mistakes. I will gladly assist you, with the Spanish language. I am learning English. Can you help me there too? I would be glad if you could write me soon.