古今论四声者多矣。寅恪於考古审音二事皆未尝致 力,故不敢妄说。仅就近日在清华园讲授所及,提出三浅显 之问题,试三简单之解答,并择录旧籍之有关者,略加诠释, 附於第二解答之後,以资参证。凡所讨论,大抵属於中古文 化史常识之范围,其牵涉音韵学专门性质者,则仅守‘不知为 不知 Ancient and modern on the four more men carry on. Yin Ke diatonic archeology have not tried hard, so dare not jump to say. Only recently taught in Tsinghua University, made the three superficial issues, try three simple answers, and select the relevant books of old, slightly annotated, attached to the second answer, with the capital certification. Where discussion, probably belongs to the scope of the common sense of cultural history of the Middle Ages, which involves the nature of phonology, only to keep ’I do not know do not know