Verb conjugation of "strecken" in German

I wanted to tell you that we have uploaded a successful version (with Peter). In Annex I send the profile. It is very similar to the last version, just a few words less in each lesson.
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.
Have you ever visited the U.S. before and if so, where have you been in the U.S.? I've been travelling in California, it was very amazing. We have traveled by car. Here are my corrections.