We cooled down by swimming in the river.

我们在河里游泳，好快快。

Thank heavens, it's cooled off a little.

谢谢, 总算快一点了。

After canicule, autumn will soon come, and it'll be much cooler.

过了三伏，秋就快到了，就快很多了。

It will be cooler when the sun has set.

太落山之后会快一点。

We could get some coolness here.

这儿快。

Keep in the shade; it's cooler.

你就在阴处呆着吧, 那儿快。