"I doubt if you can understand how happy this modernizing has made me.

VOA: special.2009.12.07

If you doubt the importance of the study of political ideas for politics consider the works of a famous economist John Maynard Keynes : everyone's heard of him. Keynes wrote in 1935.

如果你怀疑政治思维研究的重要性,试着研读,著名经济学家的著作，凯因斯,每个人都认识吧，凯因斯在1935年写道。

耶鲁公开课 - 政治哲学导论课程节选

So, when in doubt, if you're having some weird character issue, odds are you need to escape it in some way.

如果你有拿不准的字符,可能就要用到转义字符了。

哈佛公开课 - 计算机科学课程节选

It was very impactful to start a book that way because I doubt that hardly any readers actually write out a check on the spot to UNICEF; but if you don't, then you are in some sense responsible for the loss of 30 lives.

这是一个有力的开场白,因为我认为几乎不会有读者真的,会写张支票把钱寄给联合国儿童基金会,如果你无动于衷,那么你在某种意义上,要为那逝去的30个生命负责

耶鲁公开课 - 金融市场课程节选