无产阶级是普遍的阶级，他们的根本锁链是可以破裂的阶级。
The proletariat is the universal class, the class whose radical chains are capable of bursting asunder.
Psychology is the science of mental life in its adaptive relations.
唯一真正的监狱是恐惧，唯一真正的自由是从恐惧中解脱。
历史研究不仅关乎过去，也关乎理解现在和预见未来。
The rise of China represents the most significant challenge to the liberal international order since the end of the Cold War.
世界上最好和最美丽的东西是看不见甚至摸不着的——它们必须用心去感受。