语法与词汇 21.B's utterance in the following conversation exchange violates the maxim of______. A; Would you like to join us for the picnic on Sunday? B; I'm afraid I have got a class on Sunday.

A、 quality
B、 quantity
C、 relation
D、 manner

【正确答案】 A

【答案解析】合作原则下有四条准则：数量准则(the maxim of quantity)、质量准则(the maxim of quality)、关系准则(the maxim of relation)和方式准则(the maxim of manner)。本题中，这是在A、B双方都知道B没有课且可以去野餐的时候说的，因此B说的是假话，违反了质量准则。