translation.en: It's decades old, but it's becoming very trendy among police forces around the planet lately, it seems, and according to my experience as a non-voluntary breather of it, tear gas has two main but quite opposite effects.
translation.zh: 它有几十年的历史，但是最近开始流行于全球的 警察机关。 以我自己的经验，一个非自愿的吸入者 催泪瓦斯有两个非常不一样的用处