5. Irregular verbs.

1. mean - meant - meant, 2. hear - heard - heard, 3. hide - hid - hidden, 4. keep - kept - kept, 5. know - knew - known, 6. learn - learnt - learnt, 7. leave - left - left, 8. let - let - let, 9. lose - lost - lost, 10. make - made - made