Прочитайте текст и найдите соответствующий перевод подчеркнутого грамматического явления.
Like London, Moscow was never planned. It grew up around its centre, which had been surrounded by a wooden wall built by the first residents. The wooden wall was later replaced by a brick one, and palaces, cathedrals and churches were built inside it, forming what is now known as the Kremlin.
New houses were built around this centre, forming enormous rings, and the roads to other towns gradually changed into streets running across them.
защищающий
окружающий
был защищен
был окружен