But, unfortunately, there aren't good animal models for many of the diseases that we'd like to study.

但是很遗憾的是,对于很多我们想要研究的疾病,并不能找到合适的动物模型

耶鲁公开课 - 生物医学工程探索课程节选

We know that many of the for-profit models have struggled.

我们知道很多营利性的,模范网站正在挣扎。

麻省理工公开课 - 媒体、教育、市场课程节选