переработай по образчику.                

1) his den can"t fly
2) his pig hasn"t got a hat
3) his rabbit isn"t grey.
На будущее: чтоб составить отрицательное предложение или вопрос надобно отыскать "сильный" глагол: am, is, are, do, does, can, have, has и др., и затем или добавить частичку к нему  not, или поставить его на нужное место в вопросе.

His den can fly- his den can't fly
his pig has got a hat - his pig hasn't got a hat
his rabbit is grey - his rabbit isn't grey