Teacher:In this task, you're given a pair of sentences, sentence 1 and sentence 2. Your job is to determine if the two sentences clearly agree/disagree with each other, or if this can't be determined. Indicate your answer as yes or no respectively.
Teacher: Now, understand the problem? Solve this instance: Sentence 1: AC is assumed to be the principal reagent used to absorb the mercury in the exhaust gases. Sentence 2: AC isn't used anymore, we moved to different reagents years ago.
Student:
yes