This book is difficult to understand

难懂───it's hard to understand

Sometimes, it's hard to understand creature like men.───像男人这样的生物，有时候，也是很难理解的。

Sometimes it's hard to understand why designer clothes cost as much as they do.───有时我真的弄不明白为什么设计师设计的衣服会那么贵。

's hard to understand the voices?───要明白那声音说的是什么简直太难了。

So it's hard to understand why salespeople so often miss the boat and don't follow up with prospects.───所以我总是不理解为什么那些销售人员不去跟踪以致错失良机。

If I don't know where the input is coming from, it's hard to understand why I'm generating a particular set of output.───如果我不知道输入来自哪里，那么很难理解为什么我正在生成这一组特别的输出。

I know it's hard to understand, but sometimes painful things like this happen.───我知道他们很难理解这些痛苦的事情就这样发生了。

It's hard to understand how he works from the outside. He's certainly different from the others in the media.───他的工作方式让人很难捉摸，在媒体看来，他显然是个异类。

It's hard to understand each other, because our natural resources cannot support two countries like US.───要彼此理解很难，因为我们的自然资源不能支撑两个美国这样的国家。

It's hard to understand the unemployment figures when so many jobs go unfilled.

It's hard to understand her motives.

It's hard to understand the colloquial idioms of a foreign language.

It's hard to understand what's going on in Susanna's mind.

It's hard to understand how the accident came about.