My father bought a computer five years ago. It still works very well
 - The computer which my father bought five years ago still works very well.
2. There is too much light in the city at night, so we can't see stars clearly
 - If there wasn't too much light in the city at night, we could see stars clearly
3. They have built two new schools in our city this year.
 - Two new schools have been built in our city this year.
4. I don't have a lot of money, so I don't buy a lot of new books
 - If I had a lot of money, i could buy a lot of new books

1. My father bought a computer five years ago. It still works very well
-> The computer which my father bought five years ago still works very well.
2. There is too much light in the city at night, so we can't see stars clearly
-> If there wasn't too much light in the city at night, we could see stars clearly
3. They have built two new schools in our city this year.
-> Two new schools have been built in our city this year.
4. I don't have a lot of money, so I don't buy a lot of new books
-> If I had a lot of money, i could buy a lot of new books

1. My father bought a computer five years ago. It still works very well
 - The computer which.....
2. There is too much light in the city at night, so we can't see stars clearly
 - If there.....
3. They have built two new schools in our city this year.
 - Two new schools....
4. I don't have a lot of money, so I don't buy a lot of new books
 - If I.....
1. The computer which still works very well
2.If there wasnt too much light in the city at night,we could see stars clearly
3.Two new schools had built in our city by them this year.
4. If I had a lot of money,I bought a lot of new books