四级考研英语中常见的句型包括：
1. 条件句：if条件句、unless条件句、whether...or...条件句等。
- If you study hard, you will pass the exam.
- Unless you arrive on time, you will miss the meeting.
2. 倒装句：用于强调、条件句、虚拟语气等。
- Hardly had he arrived when it started to rain.
- Not only is he intelligent but also he is hardworking.
3. 强调句：it is/was...that/who...结构。
- It was not until last week that I realized the importance of time management.
4. 虚拟语气：用于表示与事实相反的假设或愿望。
- If I had known, I would have helped you.
- I wish I could go to the party with you.
5. 宾语从句：用于引导名词性从句，如主语从句、宾语从句、表语从句等。
- I believe that he will succeed in the future.
- The question is whether we should change our plan.
6. 定语从句：用于修饰名词或代词，限制其范围。
- The man who is speaking is our teacher.
- The book that you gave me is very interesting.
7. 并列句：由两个或两个以上的简单句合并而成。
- I like music, and she likes painting.
- He is tall, but she is short.
以上句型在四级考研英语中非常常见，掌握这些句型对于提高英语写作和阅读理解能力至关重要。
【考研刷题通】小程序，助你轻松备考，政治、英语、数学等考研科目全面覆盖，海量真题在线刷题，助力考研成功！快来体验吧！