But the work is hard. And getting all the oil from the seeds can be difficult.

VOA: special.2009.09.29

But,it's hard,if you're fourty-seven years, your job is a pretender to the throne, it's difficult.He had a hard time getting around.

但是,如果你要花四十七年,去争夺王位,是很不容易的,他做得很艰苦

耶鲁公开课 - 1871年后的法国课程节选

Why has it been so hard and why does it continue to be difficult to identify these pluripotent cells within tissues?

为什么会那么难呢,为什么在组织中识别多能干细胞,始终困难重重呢

耶鲁公开课 - 生物医学工程探索课程节选

It was extremely hard work under very difficult conditions.

VOA: special.2009.02.11

I cannot even make it look hard because I have memorized this problem from childhood, so there is no way I can make this look difficult.

我不会让这些问题变得看起来复杂,因为这些问题我童年时就熟记于心,我无法让它变得复杂

耶鲁公开课 - 基础物理课程节选

It was hard and difficult land.

VOA: special.2010.05.08

And if they're a premade salad then it would be even more difficult because you're not constructing it yourself, so it's hard to uses based on these sort of things.

如果那是预制色拉,就更麻烦了,因为那不是你做的,就很难进行统计

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

This proves to be really difficult in the real world because in the real world it's hard to pull apart genes and environments So, you and me will have different personalities ? Why?

这在现实中是很难区分的,因为现实中很难,把基因和环境分开来讲,你和我有不同的性格,为什么？

耶鲁公开课 - 心理学导论课程节选