Мои друзья живут в москве 5 лет.
have my friends been living in Moscow for 5 years?
my friends have been living in Moscow for 5 years, haven't they?
have my friends been living in Moscow or Samara for 5 years?
who has been living in Moscow for 5 years?
where have my friends been living for 5 years?
how long have my friends been living in Moscow( how long do my friends live in Moscow?)