3. 

1. i think i'll explore the caves

2. he doesn't know. he may take a boat trip around the island

3. Phuong, Tuan and Hoa may build sandcastles on the beach

4. My family and I will swim in the sea

5. they'll be at the seaside on Sunday

6. She'll visit the island on Monday

7. where will you be on Saturday?

8. i think Mai and I will be at school

9. the boys will be in the countryside next month 

10. i think i'll visit the mountains tomorrow

11. we will go for a picnic in the countryside

12. they will be at the seaside next week

4. 

1. C 2. B 3. A 4.  A 5. B 6. A 7. C 8. B 9. A 10. A 11. C 12. A 13. B 14. A 15. A

Nếu ở SGK hay sbt thì bn lên mạng chép cho nhanh nha đỡ bị mất điểm