Marx produced a new theory about historical change based upon conflict between competing groups.
马克思提出了一个新理论，认为历史变革是由于对立集团的冲突而产生的。
《柯林斯英汉双解大词典》
2
Because the basic idea of chaos theory is that there aren't any "models" as such—there aren't guaranteed forms, but rather patterns of change in development.
因为混沌理论的基本观点是这样的“模型”不存在——不存在确定的形式，只有发展变化中的模式。
3
Now let's look at another theory, an alternative to the hunting theory, the climate changetheory.