She hadn't been attending during the lesson.

上课时她一直不专心。

《牛津词典》

During the lesson he fell asleep.

上课的时候他睡着了。

youdao

This little boy fell asleep during the lesson.

这个小男孩在上课时睡着了。

youdao

504-- this whole course, is about this transformation, as I mentioned during the first lesson.

504这门课程的重点，是关于转变，正如我在第一课中提到的。

哈佛公开课 - 幸福课课程节选

Example: Every student pilot learns how to read an altimeter during the first lesson.

FORBES: My Ken Lay

The damage caused by high taxation during the Great Depression is the real lesson we should learn.

WSJ: Arthur B. Laffer: Taxes, Depression, and Our Current Troubles

Skibound, which organised the trip, said she was involved in an incident on a chairlift during her morning ski school lesson in the resort Claviere.

BBC: Poonam Bhattal, 13, dies on school skiing trip in Italy