EXERCISE 21. Fill in the blanks with the articles a, an, the where nec- essary 1. Russia is ... largest country in... area. 2. It extends from ... Arctic Black Sea. 3. ... President is .. head of ... state. 4. .. Sibe- Ocean to ... ria has .. continental climate. 5. ... Russia has ... world's largest oil and natural gas resources. 6. ... two-headed eagle is ... most ancient sym- bol of ... Russia. 7. symbols of ... country shouid be approved by ... ...Federal Assembly. 8. .. government of ... country is headed by ... Prime Minister. 9. ... Lake Baikal is .. deepest in... world. 10. ... thou- sands of ... tourists try to visit ... lake.

1. Russia is the largest country in the area.
Explanation: "the" is used before "largest country" as it specifies a specific country (Russia) and a specific attribute (largest).

2. It extends from the Arctic to the Black Sea.
Explanation: "the" is used before "Arctic" and "Black Sea" as they are specific bodies of water.

3. The President is the head of the state.
Explanation: "the" is used before "President" and "state" as they refer to specific roles.

4. From the Siberian Ocean to Siberia, Russia has a continental climate.
Explanation: "the" is used before "Siberian Ocean" as it is a specific ocean. No article is used before "Siberia" as it is a proper noun.

5. Russia has the world's largest oil and natural gas resources.
Explanation: "the" is used before "world's" as it specifies a specific world and its resources.

6. The two-headed eagle is the most ancient symbol of Russia.
Explanation: "the" is used before "two-headed eagle" as it refers to a specific symbol.

7. Symbols of the country should be approved by the Federal Assembly.
Explanation: No article is used before "symbols" as it is a general statement. "the" is used before "country" and "Federal Assembly" as they are specific entities.

8. The government of the country is headed by the Prime Minister.
Explanation: "the" is used before "government" and "country" as they refer to specific entities. "the" is also used before "Prime Minister" as it is a specific role.

9. Lake Baikal is the deepest in the world.
Explanation: "the" is used before "Lake Baikal" as it is a specific lake. "the" is used before "world" as it refers to a specific world.

10. Thousands of tourists try to visit the lake.
Explanation: No article is used before "thousands" and "tourists" as they are general statements. No article is used before "lake" as it is a specific lake mentioned before.