すみません、知り合いではないです。って英語でなんて言うの？

Some people have lots of friends on Facebook, most of them they do not know. That can also be dangerous, so here are some ways to express yourself to this stranger. "I'm sorry, I do not know you!" "Excuse me, I don't think we've met!"

You may well ask someone, "Do I know you?" if you cannot recall their features or anything about them, or remember seeing them somewhere before. Alternatively, you may say, "Sorry, I don't think I know you," if you are a little unsure. We all meet a lot of people over the years and in the course of our daily lives and it is hardly surprising that we may not recall everyone. This tentative question is also very polite. A final option would be, "Have we met before?"

If someone thinks you know them and you don't then you might want to clear it up and let them know you don't know them so you could simply way 'I'm sorry but I don't know you' or 'I'm sorry, I don't know who you are'

There are many ways to ask this question or address this situation. All of these examples are common ways of saying it. Asking"Who are you?" and "Do I know you?"ares probably the most direct ways of addressing this situation. But the second example is a more polite way of approaching the situation.