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: Flat screens come in ____ varieties, analog and digital.

Answer: two

Question: Tall fescue produces the ____ diazaphenanthrene alkaloids, perlolidone and perloline.

Answer: two

Question: Natural samarium is a mixture of seven isotopes, ____ of which are unstable with long half-lives.

Answer:
four