Bad books contain evil thoughts. In them, there might be much description about violence, superstition, and sex.
→ Bad books, in which there might be much description about violence, superstition, and sex, contain evil thoughts.
1. 原因状语从句：常由because, as, since和for引导
Eg: Nonetheless, I am still in favor of space travel, for its merits far outweigh demerits.
2. 让步状语从句：常由although, though, even though/ if, as long 和as not with standing引导
Eg: Although this view is wildly held, this is little evidence that education can be obtained at any age and at any place.
3. 条件状语从句：常由if, on the condition that和providing that引导
Eg: If you want to achieve something or intend to fulfill one of your ambitions, you must work hard, make efforts and get prepared.
Eg: When it comes to education, the majority of people believe that education is a lifetime study. 说到教育，大部分人认为其是一个终生的学习。
5. 目的状语从句： 常由so that和in order that引导
Eg: Millions of people have to spend more time and energy on studying new skills and technology so that they can keep a favorable position in job market.
Eg: Some people claim that government should be mainly responsible for the environmental pollution.
Eg: Many experts point out that, along with the development of modern society, it is an inevitable result and there is no way to avoid it. 许多专家指出这是现代社会发展必然的结果，无法避免。