You need to answer a given question containing a blank (_). Your answer must be one of the two objects mentioned in the question, for example "trophy" and "suitcase". Your answer must not contain a word that is not present in the question. Please don't use articles (e.g., the, a) before the answer.

The hare managed to outrun the tractor but not the spitfire because the _ was very fast.
spitfire

the box became weaker after it was soaked in water but the bowl is still strong because the _ is waterproof.
bowl

I couldn't pass my math class even though I hired a private tutor. I guess the _ was too hard.

class