句子根据内部结构可分为单句和复句。单句是短语或词充当的、有特定的语调、能独立表达一定的意思的语言单位。复句由两个或两个以上意义相关，结构上互不作句子成分的分句组成。 复句中的各个分句之间一般有停顿，书面上用逗号，分号或冒号表示；复句前后有隔离性语音停顿，书面上用句号或问号，叹号表示。
Sentences can be divided into single sentences and complex sentences according to their internal structure. A single sentence is a linguistic unit that is acted as a phrase or word, has a specific intonation, and can independently express a certain meaning. A complex sentence is composed of two or more clauses that are related in meaning and do not constitute each other in terms of structure. There is usually a pause between each clause in a compound sentence, which is indicated by a comma, semicolon or colon in writing; there are isolated phonetic pauses before and after the compound sentence, which is indicated by a period, question mark, or exclamation mark in writing.