如果你喜欢读书，你可以一直保持快乐。

You can always keep yourself happy if you like reading.

youdao

它需要源源不断的活力，不论是脑力上的，还是体力上的，需要全身心的投入，并且一直保持快乐的情绪。

It demands an unflagging intellectual and physical vigor, a total immersion, which I had to be sure that I could sustain with pleasure.

youdao

快乐工程：或者，为什么我花费一年的时间努力在早晨唱歌、清理衣柜、锻炼身体、阅读文章并且一直保持着兴趣。

TheHappiness Project: Or, Why I Spent a Year Trying to Sing in theMorning, Clean My Closets, Fight Right, Read Aristotle, and GenerallyHave More Fun.

youdao

The next day in class, I used that and I said to the students, "You know, the last thing in the world that I want you to think is that I experience a constant high or that you, by the end of the semester or the year-- it was a year course, you-- by the end of the year-- " will experience a constant high."

第二天上课时，我讲了这件事并对学生说，“我最不希望你们以为,我总是保持快乐，或者你们，在期未或学年未-,那门课程要讲一年，你们到学年未时-,会一直保持快乐“

哈佛公开课 - 幸福课课程节选