The problem is difficult to understand.

这个问题难于理解。

youdao

Gathering statistics on the scale of the problem is difficult.

按这个问题的规模来收集统计数据是有困难的。

youdao

The problem is difficult to solve in field of bellows designing.

该问题是波纹管设计的难点之一。

youdao

Today,the solution to the problem is so common that it is difficult to understand that there was a problem at all.

VOA: special.2010.07.14

Part of the problem with using operant conditioning with babies is it's difficult to get them to behave in any systematic way.

应用操作性条件作用的部分问题在于,很难使婴儿们按照系统的方式行动

耶鲁公开课 - 心理学导论课程节选

In many ways for Aristotle as it is for every student of politics the most serious the most difficult issue one confronts is the problem of faction.

从很多方面看来，无论是对亚里士多德,还是每位政治系的同学而言,最令人最感严肃,与严重的问题,是派系的问题。

耶鲁公开课 - 政治哲学导论课程节选

The problem is that those difficult economic times haven't passed the rest of the world by.

BBC: Difficult reading, difficult call

The problem is that it is difficult to conduct studies of RF in the laboratory using cells and animal models.

FORBES: Should The FCC Re-Examine Cell Phone Radiation?

The health care problem is made vastly more difficult by the immigration problem.

CNN: A GOP Contract with America for 2010