补充个例子,说下我阅读是如何训练的:
The history of clinical nutrition, or the study of the relationshipbetween health and how the body takes in and utilizes food substances, can bedivided into four distinct eras: the first began in the nineteenth century andextended into the early twentieth century when it was recognized for the firsttime that food contained constituents that were essential for human functionand that different foods provided different amounts of these essential agents.