It can be difficult to earn enough money for a family to survive.

VOA: special.2009.10.18

Yeah, it can be difficult. If you go to...

会很难。如果你去……

廉价看音乐剧的方法 - SpeakingMax英语口语达人

That means that for humans it can be a difficult and hostile place.

也就是说，它对于人类是个艰难且充满挑衅的地方。

耶鲁公开课 - 旧约导论课程节选

"I was one of these teenagers, and so I know how difficult it can be to break this habit when it's been with you for a long time,".

VOA: standard.2009.06.22

If I can just have it there before me, that is a very difficult and derivative intellectual act, and it cannot be understood as primordial or primitive.

仅是面对着它，对于思维来说非常困难，并且这不能被理解为是原始的。

耶鲁公开课 - 文学理论导论课程节选