It would be difficult, even painful,to do so.

VOA: special.2009.12.06

As you have no doubt experienced, this is a dense and difficult poem, so please reread it innumerable times for Wednesday's class, and in addition to that do the other readings assigned.

你们肯定也觉得了，这首诗很复杂很难懂，所以要一遍一遍的重复读，准备好周三的课，也要读布置的其他材料。

耶鲁公开课 - 弥尔顿课程节选

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

A newly released history of 20th Century Russia, written by a team of 45 scholars and edited by historian Andrei Zubov, includes a statement that much of the country's recent past is painfully difficult to study, which is why many refuse to do so.

VOA: standard.2009.12.25