They're small molecules that - whose principal function in the body is to carry signals from one cell in the nervous system to another.

它们都是小分子,在体内主要功能是在,神经系统内将信号,从一个细胞传导到另一个细胞

耶鲁公开课 - 生物医学工程探索课程节选

And it probably--One--There's--Evolutionary psychologists debate the function of why we talk funny to babies.

进化心理学家们在争论,我们为何要以如此好玩的方式来同婴儿讲话

耶鲁公开课 - 心理学导论课程节选