Câu 1: The Earth has existed for more than 4,000 million years.
Answer: B. has existed

Câu 2: Humans have been on the planet for just 50,000 years.
Answer: C. have been

Câu 3: Dinosaurs lived on Earth for 160 million years.
Answer: B. lived

Câu 4: In the past, people thought that the world was flat.
Answer: A. thought

Câu 5: The first Australians—the Aborigines—lived there for about 40,000 years.
Answer: D. lived

Câu 6: For many years, the USA was a British colony.
Answer: D. was

Câu 7: The USA has been an independent country for over 200 years.
Answer: A. has been

Câu 8: Before becoming a banker, my brother had worked abroad for several years.
Answer: D. had worked

Câu 9: The couple next door have lived there for twenty-five years: I’m sure they’ll never move.
Answer: B. have lived

Câu 10: He has written more than twenty books.
Answer: C. has written

Câu 11: “Where’s Roberto?” –“He’s gone home.”
Answer: B. gone

Câu 12: I’ve been to South America three times in my life.
Answer: A. been

Câu 13: ‘I’m sorry, you can’t speak to Erik—He’s gone out for lunch.’
Answer: B. gone

Câu 14: I left my umbrella here half an hour ago, and now it’s gone!
Answer: C. gone

Câu 15: How many times have you been to the supermarket this month?
Answer: A. been

Câu 16: He’s been to many places but he’s never been to Danang firework festival.
Answer: A. Been/been

Câu 17: Anna was here a minute ago. Where’s she gone?
Answer: B. gone

Câu 18: Teresa is on her way to the station and Marc has gone with her.
Answer: D. gone

Câu 19: Where have you been? We’ve got to finish this work by 5:30.
Answer: A. been

Câu 20: Have you been to Hanoi? Yes, I went there last month.
Answer: D. been

For Câu 21:

1. Rivers are one of the most natural resources.
   Answer: d. most
2. Almost every country has at least one river that plays an important part in the lives of its people.
   Answer: b. plays
3. To get water for crops, a dam is built across a river.
   Answer: d. dam
4. People can use water not only to irrigate but also to make electricity.
   Answer: c. but also
5. However, several rivers are polluted when industries develop.
   Answer: a. polluted