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.

Example Input: Sentence: At the same time, the Sudanese regime began to change.
Question: When did the regime begin to change?
Example Output: Yes.

Example Input: Sentence: In this way the other major congressional interests can be brought together in the new committee's work.
Question: How long did it take to form the new committee?
Example Output: Yes.

Example Input: Sentence: The most powerful families thus carved out for themselves whole regions that were to become the fiefdoms of Japanese feudalism.
Question: How often would one family be able to do something like this?
Example Output:
Yes.