Part 1:
1. pollution
2. celebrate
3. well
4. different
Part 2:
5. Although we are far away from each other, we still keep in touch.
6. If he didn't get up late, he would catch the bus.
7. This book was bought two days ago.
8. He said he would visit Cat Ba island after the exam.
9. She met him yesterday.
10. Nam hasn't seen his parents recently.
11. Hoa is very kind and always helps other people.
12. Our government suggests people should follow the principles of the Five-K message to prevent the Covid-19 pandemic.