7. Many people went to Han Riverto witness the Danang International Fireworks Festival.
Where did many people go to witness the Danang International Fireworks Festival?
8. We should use biogasfor cooking instead of gas.
What should we use for cooking instead of gas?
9. People use solar power for heating or cooling the house.
What do people use for solar power for?
10. Yaly Hydropower Plant was constructed in 1993.
 When was Yaly Hydropower Plant constructed?

7,Where did many people go to witness the Danang International Fireworks Festival?
8,What should we use for cooking instead of gas?
9,What do people use for solar power for?