我荒废了时间， 而今时间也荒废了我。

I have wasted time, and now the time wastes me.

youdao

一些学生可能会把假期的大部分时间都花在娱乐上，从而荒废了他们的学业。

Some students might spend most of their holiday time on amusement, and thus leave their study neglected.

youdao

这条渠荒废了。

This irrigation canal has fallen into disuse.

《新英汉大辞典》

Others though, I want to tell you that it doesn't-- if you're shopping-- I had a student come by yesterday and ask he's a little rusty in his math skills if he should take this course.

其他的,我想告诉你们不必...,如果你还在挑选课程...,昨天有个学生来问我,他的数学有点荒废了,他该不该选这门课

耶鲁公开课 - 金融市场课程节选