【正确答案】The Q-and R-principles, developed by Laurence Horn, were first proposed in his "Toward a New Taxonomy for Pragmatic Inference: Q-Based and R-Based Implicatures" of 1984, and further elaborated in his Pragmatic Theory of 1988. The Q-principle is intended to invoke the first maxim of Grice's Quantity, and the R-principle the Relation maxim, but the new principles are more extensive than the Gricean maxims. The two principles are proposed by Horn on the basis of two competing forces, the force of unification, or speaker's economy, and the force of diversification, or hearer's economy.
The Q-principle (hearer-based):
Make your contribution sufficient (cf. Quantity 1)
Say as much as you can (given R)
The R-principle (speaker-based):
Make your contribution necessary (cf. Relation, Quantity2, Manner)
Say no more than you must (given Q)
The hear-based Q-principle is a sufficiency condition in the sense that information provided is the most the speaker is able to. In the following example, (a) implicates (b).
e.g.a. Some of my friends are linguists.
b. Not all of my friends are linguists.
The R-principle, in contrast, encourages the hearer to infer that more is meant.
e.g. Canyou please close the door?
If this sentence is said in a context in which the speaker knows that the hearer's ability to do this (close the door) is not in doubt, then the hearer is licensed to infer that the speaker is doing something more than just asking him about his ability (to close the door), the speaker actually asks him to perform the act.
Q-based principle can be cancelled by metalinguistic negation, which does not affect what is said, but R-based implicatures cannot.
e.g. a. He didn't eat three carrots.
b. He ate less than three carrots.
Sentence (a) usually means sentence (b). If we stress "three" in sentence (c), which is known as metalinguistic negation, then (b) is cancelled, and we can follow it with (d)
c. He didn't eat THREE carrots.
d. He ate FOUR of them.

【答案解析】[解析] 本题考查Hom的数量原则和关系原则。Hom认为，格莱斯的会话准则，以及由此推导出来的含义主要是来自这两种竞争力量。他建议把格莱斯的准则简化为Q原则和R原则。Q原则源于格莱斯的数量准则第一条次则，R原则源于关系准则。但二者都比格莱斯的准则内容更宽泛。