2. fill in the article (a/an, the) where it’s necessary. 1. … mark twain is famous for his book “the adventures of tom sawyer” 2. … smiths have … dog and … cat. 3. “is this your friend? ” — “no, it isn’t my friend, it is my sister”. 4. this is tree. tree is green. 5. i can see three children. children are playing in … yard. 6. what's … highest mountain in the world? 7. he lives in … paris. 8. he is … economist. 9. … earth goes round … sun. 10. what … strange girl! 11. could you close … door, please? 12. we celebrate new year on … 31st of … december. 13. it is washed by the waters of … atlantic ocean. 14. are you studying foreign languages at school, like … french? 15. … moscow is on … moskva river.