Question

2.  ―Did you enjoy yourself yesterday?

―Yes. As you saw, the party went on in the most pleasant atmosphere.

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Answer 1

2.  most前的the改为a句意："昨天你玩得愉快吗？""是的，正如你看见的，聚会在一种非常愉快的气氛中进行。"a most pleasant atmosphere —种非常愉快的气氛；the most pleasant atmosphere最愉快的气氛。这句话没有比较范围，所以不用最高级。此处most表示"很，非常"。