Accent is something somewhat difficult to define and categorize.

重音是很难定义和分辨的。

耶鲁公开课 - 现代诗歌课程节选

That's a complicated thing that accountants figure out and accountants find it difficult to define the earnings of a company, but they do something and they come up with a number.

会计们会计算这个复杂的问题,他们还会发现公司收益很难定义,但是他们会想办法,得出一个数字

耶鲁公开课 - 金融市场课程节选