In some cases, the tenses of the Perfect Continuous group are replaced by the correspondent tenses of the Perfect group. This replacement is:

  • Obligatory:

    • With verbs that are not used in Continuous tenses.

      They have been married for two years.
      Они женаты уже два года.

    • In the Passive voice to avoid too long verbal forms.

      This question has been discussed for two hours.
      Этот вопрос обсуждают уже два часа.

  • Not obligatory but wishful in negative sentences.

    I haven't read any English books for several months.
    Я не читал ни одной книги на английском уже несколько месяцев.

  • Not obligatory with so-called non-terminative verbs - to live, to work, to study, to learn.

    I've been living in this city all my life. = I've been lived in this city all my life.
    Я живу в этом городе всю мою жизнь.