Fill in with if or unless

1. [ ] you run fast, you'll miss the train.
2. [ ] the shoes fit, I will buy them.
3. She won't go to work tomorrow
   [ ] she is feeling better.
4. [ ] you finish your homework quickly, we will watch a DVD.
5. Don't do the washing-up
   [ ] you want to.
6. [ ] I see Nigel, I'll tell him to send you an email.