1. Historical events: Historical events are commonly used materials in argumentative papers, which can be used to demonstrate opinions and analyze problems. For example, the Nazi Holocaust in World War II can be used to demonstrate the cruelty of war and the importance of peace. China's reform and opening up can be used to demonstrate the necessity and achievements of reform.

2. Famous sayings: Famous sayings are authoritative and persuasive and can be used to support opinions or lead to topics. For example, Martin Luther King's "Ihaveadream" can be used to demonstrate the importance of equality and freedom; Jobs's "Stayhungry, stayfoolish" can be used to demonstrate the importance of innovation and pursuit.

3. Literary works: Plots and characters in literary works can be used to demonstrate opinions or lead to themes. For example, Hamlet's revenge can highlight the importance of morality and justice; Jane Eyre's self-struggle can prove the importance of women's independence and self-esteem.

4. Social phenomena: Social phenomena can be used to demonstrate opinions or lead to themes. For example, cyber violence can be used to demonstrate the importance of cyber literacy and morality; Environmental pollution can be used to prove the importance of environmental protection and sustainable development.

5. Scientific theory: Scientific theory can be used to demonstrate opinions or lead to topics. For example, Darwin's theory of evolution can be used to demonstrate the importance of survival of the fittest and natural selection; Einstein's theory of relativity can be used to demonstrate the scientific spirit and the importance of exploring the unknown.

6. Philosophical thoughts: Philosophical thoughts can be used to demonstrate opinions or lead to themes. For example, Zhuangzi's "Happy Travel" can be used to demonstrate the importance of freedom and freedom; Kant's moral philosophy can be used to demonstrate the importance of morality and responsibility.