这桌子不用时可以折叠起来。

The table folds up when not in use.

《牛津词典》

当不连续标记是必要的，不用时。

When discontinuity marker is necessary and when not.

youdao

很多设备在不用时仍耗电。

Many devices use electricity even when you are not using the device.

youdao

But so when I say "family"-- we try to avoid even talking about "the Roman family," because it means something so different to them than what it means to us.

所以我说家庭时-,我们尽量不用来指“罗马家庭“,因为这个词古今意思截然不同。

耶鲁公开课 - 新约课程节选