The TOEFL iBT Reading section assess how well you can read and understand materials used in an academic environment.
It includes three or four reading passages, each approximately 700 words long, with 10 questions per passage. You have 54 to 72 minutes to answer all the questions in the section.
Reading passages are excerpts from university-level textbooks that would be used in introductions to a topic. The passages cover a variety of subjects. Don't worry if you're not familiar with the topic of a passage. All the information you need to answer the questions will be included in the passage. There is a glossary feature available to define words not commonly used, if you need it.