One of the main reasons people exercise is to control or reduce their weight.

VOA: special.2010.06.08

I've got three main reasons, they're: adverse selection, moral hazard, and liquidity.

我总结出三个主要原因,分别是,逆向选择,道德风险,及流动性

耶鲁公开课 - 金融市场课程节选

It doesn't work that way for a variety of reasons, but the main reason is that you want some decisions to be made at each space between two cells.

这出于很多原因,但主要的原因是,在每个细胞间隙,都需要决定信息是否继续传递

耶鲁公开课 - 生物医学工程探索课程节选

The report identifies five main reasons for losses in biodiversity.

VOA: special.2010.05.25