The classes were all held (verb) in the morning (adverb).
Work began (verb) promptly at nine o’clock (adverb).
The students found the illustrations (noun) of the problem (adjective) interesting and helpful.
Teachers located materials (noun) on different topics (adjective).
Classes (noun) like these (adjective) kept the students busy
B is the correct answer. Querulous is "complaining in a petulant way or whining" manner
Hope this helps!
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This means that the pressure is high, but there can be different ways to put it. (I'm unfortunately not 100% sure.
