Ответ:
1. You don't have to run. You won't miss the bus.
2. Pete's eyes are very bad, and he has to wear glasses.
3. School starts at eight o'clock, so we have to get up early.
4. My friend will give me some tickets for the concert, so I didn't have to pay!
5. We have to study maths at school, because it's compulsory.