Ответ:

  1. Mark has got a black car.
  2. You have got a red pen.
  3. They have got a new ball.
  4. Cats have got long whiskers.
  5. I have got a cat.
  6. She has got an old computer.
  7. Robert and I have got short hair.
  8. Robert and you have got glasses.
  9. Rabbits have got long ears.
  10. The English girl has got a grey school uniform.
  11. The flowers have got pink petals.
  12. My brother has got a big bedroom.

В рукописных ответах нужно исправить № 4, 9 и 11: с существительными во множественном числе употребляется have.