本文检讨了现代汉语研究历史上提出过的划分句类所依据的两个标准——句子的用途和语气,指出句类是句子的形式分类,它的确定必须有形式特征作为依据,把句类看作是句子的用途分类,或者将句类等同于句子的语气分类,都容易造成误解。本文还对情态、语气等概念做了明确的界定。 This paper reviews the two criteria on the basis of which two categories of sentences are proposed in the history of modern Chinese studies - the purpose and tone of the sentence, the sentence classification as the formal classification of sentences, the determination of formal sentences as the basis for determining sentences, It is easily misunderstood as a classification of the purpose of a sentence or as a classification of a sentence as the tone of a sentence. This article also made a clear definition of modality, tone and other concepts.