留学写作中常用的英语句式包括：
引言（Introduction）:
There is evidence that [topic] plays a crucial role in [field].
In recent years, there has been an increasing interest in [topic].
The purpose of this study is to [describe the purpose].
文献综述（Literature Review）:
Extensive research has shown that [statement about previous research].
Previous studies of [topic] have not dealt with [specific aspect].
Up to now, far too little attention has been paid to [topic].
研究现状（Current Research Situation）:
There is a growing body of opinion that [statement about the current situation].
An increasing number of people have the tendency to [describe a trend].
研究目的（Research Purpose）:
This investigation aims to [describe the specific goals of the study].
研究意义（Significance of the Study）:
This study provides new insights into [describe the contribution of the study].
文章结构概述（Structure of the Paper）:
This paper begins by [describe the first part of the paper].
It will then go on to [describe the subsequent parts].
引出开头（Opening Sentences）:
It is well-known to us that [statement of fact].
Recently, the problem of [topic] has been discussed.
简单句、并列句和复合句:
Simple sentences: contain one independent clause.
Coordinated sentences: use coordinating conjunctions like and, but, or.
Subordinate sentences: contain a main clause and one or more subordinate clauses.
以上句式可以帮助留学生在撰写英语论文时更加流畅和准确地表达观点。记得在写作时，根据上下文选择合适的句式，并保持句子之间的逻辑连贯性
