1, They made the fire in the traditional way.
-> the fire was made in the traditional way
2, How many festivals do people celebrate in January?
-> how many festivals is celebrated in January?
3, People throw away millions of bottles every day.
-> millions of bottles are thrown away every day
4, How do they cook this kind of good?
-> how is this kind of food cooked?
5, They will have to repaint their house.
-> their house will be painted 
6, Have you tidied your room?
-> Have your room be tidied?