A question that is free of any grammatical or logcal errors, should be labeled 'yes', otherwise it should be indicated as 'no'. A question is grammatically correct if all its entities i.e. nouns, verbs, adjectives, prepositions, pronouns, adverbs are at appropriate position. A question is logically correct if the semantic makes sense.
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Question: Sentence: The two become close friends but do not reveal the secrets .
Question: How long did it take them to become friends?

Answer: Yes.

Question: Sentence: This is an astonishing new record for a coin, he said.
Question: What day was the record established?

Answer: Yes.

Question: Sentence: In 1996 the WHO found that much of the population existed in a state of ''semi-starvation.''.
Question: How often does the WHO find out facts about the population?

Answer:
Yes.