"All of this is contributing to an underground, sort of 'black' economy, which is very difficult for any of us to measure and gauge.

VOA: standard.2010.06.17

I don't want to have to deal with heat escaping to the outside environment in a way that might be difficult or complicated to measure or calculate.

我可不想处理跑到,环境中去的热量，那测量或,计算起来会非常麻烦和复杂。

麻省理工公开课 - 热力学与动力学课程节选

It also is a good lesson in how difficult it is, and we'll talk about this in a subsequent class, to actually measure what people eat.

同样这能很好的说明,实际评价人们的饮食有多困难,我们下节课会讨论这个话题

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选