You handle them very special in terms of being extra careful in a very high ventilation area, in hoods is how you handle them.

在使用它们的时候你需要格外小心,必须在通风条件非常好的地方，在通风柜中才行。

麻省理工公开课 - 化学原理课程节选

but you've got to be certain when you get out there. And make a positive move.

但是你在外面，你必须要小心。然后积极行动。

我使用自行车 - SpeakingMax英语口语达人

We think a lot about weight in this country, but weight is a remarkably carefully controlled parameter of a person, that is, you have to work pretty hard to gain weight or to lose weight.

我们身在一个特别关注体重的国家,然而体重是一个,需要小心地控制地人体指标,这就是说,你必须付出相当多的努力,才能增加或减少体重

耶鲁公开课 - 生物医学工程探索课程节选

And he said, "Tal, you'll have to be careful."

他说“Tal，你必须小心“

哈佛公开课 - 幸福课课程节选