"Are you cooking dinner already?"
Translation:Ты уже готовишь ужин?
Why is "dinner" translated by "ужин"? Shouldn't it be "обе́д"? Reference: http://en.bab.la/dictionary/english-russian/dinner
It's like 'du' and 'Sie' in German or 'tu' and 'vou' in French. Plural 'you' is used as the formal singular 'you'. 'Вы' is used when you speak to someone who is older, higher in authority, respect or standing or a stranger. 'Ты' is used when you speak to a good friend or a (significantly) younger person/ child.