Tu and vous
Tu and vous, I don't know when i should use tu or when i shoud use vous. They both mean you but which one fits the sentence and how do you tell them apart? Please help.
Tu is singular, if you're talking to one person. Vous is plural, if you're talking to more than one. In English, we don't have a different plural word for "you." Vous is like saying "all of you" or "you guys."
To complicate things a bit, in French you always use vous to be polite, and only use tu with people you know well. So in an actual conversation, it can be a good rule of thumb to just use vous if you're not sure. But in a translation context like this website, stick with the singular/plural usage of you to be accurate.
Tu is familiar, while vous is formal.
You would use Tu with your wife or friend, while you would use vous in more formal speech.
My general rule of thumb when I'm speaking to a French person is to use "vous" until the moment they "tutoyer me" or use "tu" with me, and then you know that you have passed that boundary with them where they are familiar enough with you that you can use "tu" with them. This will usually happen in the first 5 minutes of a conversation - unless in a formal setting like at the doctor's when you are buying something in a shop, for example.
Also, if you are younger like me (I'm 25) and you run into other people around your age and in their 20s and younger, then you almost never really need to use "vous" with them (although I agree with kitkatkelly that if you are unsure, ALWAYS use vous). Conversation is much less formal with young people.