在网络作文的结尾，通常使用以下表达来结束文章：

"In conclusion," 意为“总之”，用来概括全文的主要观点。例如：
In conclusion, it is clear that social media has both positive and negative effects on society.
"To sum up," 意为“总而言之”，用来概括全文的主要观点。例如：
To sum up, the benefits of exercise far outweigh the risks.
"In summary," 意为“总结”，用来概括全文的主要观点。例如：
In summary, the evidence suggests that a plant-based diet can have numerous health benefits.
"To conclude," 意为“最后”，用来结束文章。例如：
To conclude, it is important for individuals to be aware of the impact their actions have on the environment.

这些表达都来自英语写作中常用的结尾语，可以在网络作文或其他类型的文章中使用。在选择使用哪种表达时，应该考虑文章的整体风格和语言氛围，选择合适的表达方式。