在英语四级作文中，使用一些常用的句型可以提升作文的表达能力和逻辑性。以下是一些常用的英语四级作文句型：

1. Introduction 句型：
- Nowadays, it is widely believed that... 如今，人们普遍认为...
- With the development of society, the issue of... has aroused wide concern. 随着社会的发展，...问题引起了广泛关注。
- In recent years, there has been a growing concern about... 近年来，...问题引起了越来越多的关注。

2. 表达观点句型：
- From my perspective, ... 从我的角度来看，...
- It is widely acknowledged that... 众所周知，...
- It is undeniable that... 不可否认的是，...
- It is clear that... 很明显，...
- It is worth noting that... 值得注意的是，...

3. 表达原因句型：
- There are several reasons why... 有几个原因导致...
- One of the main reasons is that... 其中一个主要原因是...
- Another contributing factor is... 另一个促成因素是...
- A further reason is... 进一步的原因是...
- What accounts for this phenomenon is... 造成这一现象的原因是...

4. 表达优缺点句型：
- On the one hand, ... On the other hand, ... 一方面，...另一方面，...
- The advantages of... outweigh its disadvantages. ...的优点大于其缺点。
- Although... has its drawbacks, the benefits it brings are far more significant. 尽管...有其缺点，但它带来的好处更为显著。

5. 结论句型：
- In conclusion, ... 总之，...
- To sum up, ... 总而言之，...
- Therefore, it is necessary/important/essential to... 因此，...是必要的/重要的/必不可少的。
- In a word, ... 一言以蔽之，...

以上句型只是一部分常用的句型，建议在备考过程中积累更多的句型，并根据具体的作文题目和内容进行灵活运用。同时，要注意句子的结构和语法的正确性，以确保作文的流畅和准确。