Помогите
Change the sentences keeping the same meaning.
1. Joe collected his stamps in 3 years.
It took....
2. Joe is looking for some new stamps with his friend now.
Joe and his friend....
3. Stamps with flowers cost less than the others.
Stamps with flowers weren't....
4. I want to do well on the test, so I can go to the University.
If....
5. It was a mistake not to study for the exam.
Not....