Put the verbs into the correct tense

1. They
   [ ] the bus if they had known it was going to be so crowded.
2. When water
   [ ], it
   [ ] into ice.
3. If I
   [ ] you, I
   [ ] your mum's advice.
4. If only I
   [ ] those boots when I had the money.
5. I wish he
   [ ] me more often.
6. Unless Hattie
   [ ] harder, she
   [ ] her exams.