As Rosemary grew older, she became increasingly difficult to live with and supervise.

VOA: special.2009.08.23

Now the question is "how does it expand" and "why is it so difficult for us to understand, accept, assimilate and live according to the fact that we can make a difference, if we understand that what we need to understand is how change happens.

问题是“它如何扩大“,以及为什么我们难以理解，我们能够做出改变这个事实,并接受，被同化以及据此生活，如果我们能了解我们需要理解的,是改变如何发生。

哈佛公开课 - 幸福课课程节选

Ida Tarbell found it difficult to live in Paris without much money.

VOA: special.2010.04.25

However,this is more difficult because it is harder to control the diets of people and because they live longer than other animals.

VOA: special.2009.09.01

So they quickly passed a bill that made it much more difficult for Chinese citizens to come to live in the United States.

VOA: special.2010.03.11

Many southerners live in remote areas difficult to access by road, and many roads become impassable during rainy season.

VOA: standard.2010.03.23