Translation of succession in German

I know it is a little confusing. The problem is if the original word is a conjugated verb: I skipped them until now. I did not write it in my explanations. It actually must be skipped. Thanks for noticing.
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.
Three years ago I was with my friends in South Korea whom I met in my English class in Washington. Then I was in America for another three years, one in Oklahoma and two in Alabama.