Объясните использование грамматических форм (отмечены звездочками) в следующих предложениях из текста.

1.Russia *is* the largest country in the world. It *lies* in the Eastern part of Europe and in the Northern part of Asia.

2. Russia *is washed* by twelve seas and three oceans.

3.*There are* three main mountain chains in Russia. The Urals *separates* Europe from Asia.

4.Russia *is* a land of long rivers and deep lakes.

5.Numerous canals *join* all the rivers in the European part of Russia making it the largest inland water transportation route in Europe.

6.The history of Russia *dates* back to the year 862.

7.The history of Moscow *is connected* with the history of Russia.

8.It *is* a political, administrative, economic, industrial, scientific, educational and cultural centre of the country.

9.The army *had* to retreat.

10.That *was* a poor substitute for the military triumph in Russia, so much desired by Napoleon.