Fires thin out the dense, flammable undergrowth.

野火使原本茂密、易燃的树丛变得稀疏。

Up this high, the trees start to thin out.

这里海拔高，树木都开始变得稀疏了。

Smaller fires used to happen naturally which thinned out the forests.

过去，较小的火灾通常是自然发生的，这会使森林变得稀疏。

By the time she came back, the queue had thinned out a little.

等她回来时，排队的人已经少了一点。

Eventually, the gas expands so much it thins out, and it stops glowing.

最终，气体会膨胀到变薄，停止发光。

Lake beds evaporated and then filled, herds thinned out and then grew bigger.

湖床干了又湿，兽群数量减了又增。大地被阳光炙烤后，又被雨水淹没。

You had full trains well past 2, and then things seemed to thin out.

因为凌晨两点以后还有地铁运行，所以客流量得到了缓解。

Sometimes that's because the gas thins out, so there's not enough stuff there to get lit and see.

有时那是因为气体变稀薄了，所以没有足够的物质可以被点燃和看到。

As you get further down, the oil thins out.

当你继续往下走时， 油会变稀。

And I'm thinning it out as I'm doing it.

我在做的时候正在把它变薄。