四级写作常见话题及范文：人类疾病

　　Human Disease, in medicine, any harmful change that interferes with the normal appearance, structure, or function of the body or any of its parts. Since time immemorial, disease has played a role in the history of societies. It has affectedand been affected byeconomic conditions, wars, and natural disasters. Indeed, the impact of disease can be far greater than better-known calamities.