说明文是我国语文教学的三大文体之一，说明文的阅读对初中学生逻辑思维的发展具有重要作用。然而，不同类型说明文阅读具有一定差异，已有研究缺乏对不同类型的说明文的分析。本研究针对221名初中生，分析初中生说明文的阅读表现，对比描述类说明文和问题解决类说明文的阅读表现差异，并基于文本-读者-任务理论模型探究影响说明文阅读表现的因素，分析在不同类型阅读任务中工作记忆、结构意识等读者因素对说明文阅读表现的影响。

结果发现：在阅读表现方面，描述类说明文与问题解决类说明文阅读表现具有显著的差异。从阅读整体表现来看，描述类说明文优于问题解决类说明文；从各个具体的维度来看，无论是信息提取、整体感知，还是推论阐释维度，描述类说明文均优于问题解决类说明文。

在影响变量方面，第一，结构意识对描述类说明文和问题解决类说明文的阅读表现有直接的正向作用，这意味着结构意识越强的学生，阅读表现要更佳。第二，工作记忆对描述类说明文和问题解决类说明文的阅读表现有间接的正向影响。第三，性别对描述类说明文和问题解决类说明文的阅读表现没有影响。第四，家庭经济背景对描述类说明文和问题解决类说明文的阅读表现具有间接的正向影响。

基于上述研究结论，本研究对一线的说明文结构教学提出了如下建议：第一，教师要关注说明文的类型特点，提高说明文教学针对性；第二，教师要关注说明文的结构，循序渐进地增强学生结构意识；第三，教师要关注说明文的重要信息，有效提升各类学生说明文阅读成效，例如抓信号词，画结构图。

总的说来，本研究揭示了描述类说明文和问题解决类说明文阅读表现的差异，以及影响因素的差异。未来研究还可以在如下方面进行改进：样本量还需进一步延展；说明文文本的类型在范围上还需进一步扩展，影响因素的研究还需进一步深入。

Exposition is one of the three major styles of Chinese language teaching in China, and its reading plays an important role in the development of logical thinking among middle school students. However, there are certain differences in the reading of different types of exposition, and existing research lacks analysis of different types of expository texts. This study analyzed the reading performance of 221 junior high school students' expository texts, compared the differences between descriptive expository texts and problem-solving expository texts, explored the factors affecting the reading performance of exposition based on the text reader task theoretical model, and analyzed the impact of reader factors such as working memory and structural awareness on the reading performance of exposition in different types of reading tasks.

The results showed that there was a significant difference in reading performance between descriptive and problem-solving explanatory texts. From the perspective of overall reading performance, descriptive expository texts are superior to problem-solving expository texts; From various specific dimensions, whether it is information extraction, overall perception, or inference interpretation, descriptive expository texts are superior to problem-solving expository texts.

In terms of influencing variables, firstly, structural awareness has a direct positive effect on the reading performance of descriptive and problem-solving explanatory texts. This means that students with stronger structural awareness have better reading performance. Second, working memory has an indirect positive impact on the reading performance of descriptive expository texts and problem-solving expository texts. working memory affects the reading performance of expository texts by influencing structural awareness. Thirdly, gender has no effect on the reading performance of descriptive and problem-solving explanatory texts. Fourthly, family economic background has an indirect positive impact on the reading performance of descriptive and problem-solving explanatory texts.

Based on the above research conclusions, this study proposes the following suggestions for teaching the structure of expository texts on the frontline: firstly, teachers should pay attention to the types and characteristics of expository texts and improve the targeted teaching of expository texts; Secondly, teachers should pay attention to the structure of explanatory texts and gradually enhance students' awareness of structure; Thirdly, teachers should pay attention to the important information in expository texts and effectively improve the reading effectiveness of various types of students' expository texts, such as grasping signal words and drawing structural diagrams.

Overall, this study reveals the differences in reading performance and influencing factors between descriptive and problem-solving explanatory texts. Future research can also be improved in the following areas: the sample size needs to be further expanded; The type and scope of expository text still need to be further expanded, and the research on influencing factors needs to be further deepened.