"It is very difficult to really pin down and there have been these sorts of accusations from the Revolutionary Guards in the past."

VOA: standard.2009.10.18

But then also a little bit about your history, where you come from, some of your experiences which have helped you or informed your opinions on this very difficult issue that the entire world really is spending a lot of time trying to work on.

然后再谈谈你们各自的经历，你们从何而来，谈一些你们自己的经历,一些帮助过你们，或形成了你们,就这个复杂问题的观点,这个全世界都在投入大量时间试图解决的问题。

普林斯顿公开课 - 人性课程节选

Oh really? I imagine that it must be very difficult to drive in a big city like New York.

是吗？在大城市开车肯定会比较困难，比如在纽约。

Do you ever实战 - SpeakingMax英语口语达人

So I will be really excited to do that, but that is very difficult to get.

如果能成功的话我真的很高兴，但是这个奖学金很难申请到。

耶鲁的著名人士 - SpeakingMax英语口语达人