Subject and verb change their position in statement and question.
|statement||You from Germany.|
|question||you from Germany?|
We always use the short answer, not only "Yes" or "No". This sounds rude.
If the answer is "Yes", we always use the long form.
Example: Yes, I am.
If the answer is "No", we either use the long or the contrated form (short form).
Example: No, I am not - No, I'm not.
|Are||Peter and John||from England?||Yes,||they||.|