instants是什么意思？

An instant is an extremely short period of time.

If you say that something happens at a particular instant, you mean that it happens at exactly the time you have been referring to, and you are usually suggesting that it happens quickly or immediately.

To do something the instant something else happens means to do it immediately.

You use instant to describe something that happens immediately.

Instant food is food that you can prepare very quickly, for example by just adding water.