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I/
1. Where did you buy this T-shirt for your brother?
2. How often do you get to the music festival?
3. Why did your friends save money?
4. When did you go to the Flower Festival in Da Lat?
5. What do the Vietnamese decorate their houses during Tet?

II/
1. A -> disappointed
2. She would be pleased if you got in touch.
3. D -> come
4. A -> angry 
5. B -> she

Ex3/
1. stayed/was staying/met
2. am going to go/ is going to stay/wants
3. don't start/will miss
4. am meeting/ has just come
5. is writing
6. was playing/arrived
7. have grown/was

IV/
1. The room is cleaned every day.
2. I will be collected at the airport by John.
3. Football is played all over the world.
4. Many accidents are caused by careless driving.
5. The glass bottles will be broken into small pieces.
6. The small glass pieces will be melted under heat. 
7. The garbage is cleaned by us every day.
8. This machine mustn't be used.