Translation of Überschreitung

Boston is kind of huge neighborhood, generally very friendly people and you may meet many people that you already know. So it is pretty easy to get used to and if you grow up there, you don't wanna leave. If you do, you are going to miss it terribly.
My correction were added and highlighted with yellow markers and attached to this email. Tell me now if you have any questions about grammar rules, since I was a teacher 10 years ago.
What is the past tense of 'to swim'? So either you say, I was swimming or yesterday I was swimming. Or: I was running yesterday vs. yesterday, I ran. You know the answer? I have no clue.