They found that climate changes "are already exerting a considerable drag on yield growth" and may have affected food prices.

VOA: special.2011.05.17

The "but" is that there are other ways we could model imperfect competition, and, as we're going to see today, they yield different answers.

但是"是指,通过其它方式也能获得不完全竞争模型,并且,就像我们今天会看到的,它们会产生不同的结论

耶鲁公开课 - 博弈论课程节选

They like to--when they're computing the investment yield, they want to be completely honest and not use any rules of thumb.

当他们计算投资收益率的时候,他们需要完全精确,而非用经验公式

耶鲁公开课 - 金融市场课程节选