Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.
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Question: Airplanes still fly four to ____ times faster than zeppelins.

Answer: five


Question: Some tropical species have ____ or three generations per year.

Answer: two


Question: Volcanoes emit ____ sorts of ozone-depleting compounds.

Answer:
two