The table folds up when not in use.

这桌子不用时可以折叠起来。

《牛津词典》

In order to successfully refer when we use language, there must be an appropriate relationship between the speaker and the object referred to.

为了在我们使用语言时成功引用，说话者和被引用的对象之间必须有合适的关系。

youdao

I also mention in my book that when we use the OO paradigm, it is not easy to represent graphically at all times where our application is.

在书中我还提到，当我们使用 OO 范式的时候，要在任何时间图形化地表示出我们的应用程序在哪里并不容易。

youdao

Ships no longer in use contain dangerous materials which can be released into the environment when they are taken apart.

VOA: special.2009.04.27

It is essentially equal to internal energy for condensed systems, but when you look in the books sometimes they will use this term.

它与内能是相同的,在凝聚体系中，在你看书时有时你会发现,它们会这样使用。

麻省理工公开课 - 固态化学导论课程节选

In another example, you can use a "when" question in order to ask about the timing of a specific event.

在下面这个例子中，你可以用When 问句来询问一个具体活动的时间。

When 课堂 - SpeakingMax英语口语达人

SlimPort accessories maximize the battery life, while also providing the option to charge the mobile device when in use on the auxiliary screen.

ENGADGET: Nexus 4 boasts SlimPort support for tethered display sharing

Mr Clarke said many of the patterns used in British sign language were the same in Welsh, but there were differences in the way certain patterns were structured when adapted for use in the Welsh language.

BBC: Legal threat over lack of Welsh-medium signer for deaf girl

When the iPads are not in use or when the "iBusiness" is parked they can be stored securely and hidden from sight in custom-tailored compartments in the BRABUS center console.

ENGADGET: Brabus iBusiness luxury sedan puts an iPad at every seat, a Magic Mouse at every hide-covered armrest