You don't have to work very hard to figure out what these different facial expressions mean.

你不必努力地去学习,去辨析不同面部表情的含义。

耶鲁公开课 - 心理学导论课程节选

I'm afraid that you are sleeping, continue working hard.

我担心你睡着了，要继续努力学习哦！

I'm afraid of 课堂 - SpeakingMax英语口语达人

It turns out that if you start learning a language, a second language is where most of the work's been done, within the first few years of life you're fine.

如果你在出生的头几年里开始学习一门语言,非常努力地学习了第二门语言,那么你一切正常

耶鲁公开课 - 心理学导论课程节选