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: Infected rodents carry and secrete the virus for about ____ days.

Answer: seven


Question: Fuzzy logic is an attempt to combine the ____ techniques.

Answer: two


Question: Furrow irrigation is used for crop production in all ____ systems.

Answer:
four