学界对于汉语中“无定NP主语句”的研究一直没有停止过，本文将研究重点放在与无定NP主语句相关的“有”字句和“是”字句上，立足语料，在信息结构的框架下对与无定NP主语句相关的“有”字句和“是”字句进行了考察和分析。文章共分为六个章节： 第1章为绪论，主要介绍了论文的选题缘起、研究对象和内容、研究所使用的相关理论、语料来源和前人研究综述。本文的研究对象主要是与无定NP主语句相关的“有”字结构和“是”字结构，研究中应用的信息结构理论主要来自Lambrecht（1994）搭建的信息结构框架。 第2章论述了汉语中的“有”和“是”在语义、概念结构和句法等方面的同一性。 第3章从话语功能的角度对无定NP主语句、“有+无定NP+VP”和“是+无定NP+VP”进行了考察和分析，发现其既有相同之处，又有不同之处。相同点是这三类结构都通常多用来叙述一个事件或描述一种状态，都有“存在”、“出现”的含义，都能用来引入新的指称对象，传递新信息。不同点主要在于“有+无定NP+VP”和无定NP主语句出现的环境重合度较高，在“报道”和“叙述”事件时均出现得较多，但“是+无定NP+VP”没有多用于“报道事件”的倾向。此外在出现环境上，三者也存在一定差别。 第4章主要考察了“有+无定NP+VP”和“是+无定NP+VP”在信息结构上的异同，二者都为类双小句结构，且都可以认为是以实体为中心的无分判断和以这个实体为话题的二分判断的融合，二者的不同主要体现在这两个判断在两个结构内部的句法地位和语义贡献的差异。 第5章主要从分裂句角度的对“有+无定NP+VP”和“是+无定NP+VP”进行考察，认为二者都是汉语中的分裂结构。但它们所标记的焦点结构类型上存在差异，“有”字结构通常只用来标记句子焦点，而“是”字结构既可以用来标 记句子焦点，又能够标记论元焦点。 第6章对文章进行了总结。

The academic circles have never stopped studying "the unidentifiable NP subject sentence" in Chinese. This paper will focus on the "You（有）" and "Shi（是）"constructions related to the unidentifiable NP subject sentence, based on the corpus, under the information structure theory. Under the framework, the "You（有）" and "Shi（是）"constructions which related to the unidentifiable NP subject sentence are investigated and analyzed. This paperconsists of six chapters: Chapter 1 is the introduction, which mainly contains the origin of the theme, the objects and contents of the research, the theoretical basis used in the research, the source of the corpus and the review of previous studies. The research object of this paper is mainly the "You（有）"construction and the "Shi（是）"construction related to the unidentifiable NP subject sentence. The information structure theory applied in the research mainly comes from the information structure framework built by Lambrecht (1994). Chapter 2 isabout the semantics of "You（有）" and "Shi（是）" in Chinese. When expressing the meaning of "existence", the two characters are very similar. In Chapter 3,we analyzethe unidentifiable NP subject sentence，"You（有）+unidentifiableNP+VP" and "Shi（是） + unidentifiableNP+VP" from the perspective of discourse function, and finds that they have both the same and the difference. The same point is that these three types of constructions are often used to describe an event or describe a state.All of the have the meaning of "existence" and "appearance".They can be used to introduce new referent and deliver new information. The main difference lies in the fact that there is a high degree of coincidence in the presence of "You（有）+unidentifiableNP+VP" and unidentifiable NP subject sentence, and there are more occurrences in the "report" and "narrative" events, but "Shi（是） + unidentifiableNP+VP" does not have the tendency to "report events." In addition, there are certain differences in the environment. In Chapter 4,wetalk about the similarities and differences between the information structure of "You（有）+unidentifiableNP+VP" and "Shi（是） + unidentifiableNP+VP", both of them are like bi-clausal constructions , and can be considered as entities. The fusion of the center's undivided judgment and the binary judgment with this entity as the topic, the difference between the two constructions is mainly reflected in the difference of the syntactic status and semantic contribution of the two judgments within the two structures. In Chapter 5,wefocus on the "You（有）+unidentifiableNP+VP" and "Shi（是） + unidentifiableNP+VP"in the perspective of cleft constructions,and they are both cleft constructions in Chinese. However, there are also differences in the types of focus structures that are marked bycleft constructions. The "You（有）"constructionsare usually only used to mark the sentence-focus, and the "Shi（是）"constructions can be used to mark both the sentence-focus and the argument-focus. In Chapter 6 we make a summaryof thepaper.