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1. It is hard to know exactly when Ho Chi Minh city's metro will open.
2. It is impossible to do this project in 24 hours.
3. It is important to take a break twice a day.
4. It is possible to work on your own projects.
5. It is exciting to be here.
6. It is annoying to wait in a long line of traffic.
7. It is necessary to wear uniforms at our school.
8. It was nice of her to give me the last of her cake.
9. It was eye-opening to learn about the old transport sysetm in Ha Noi.
10. It is very hard to remember all the Maths formula.