第二年第一百八十三天

[nnozomi]

语法
当 + X + 的时候, "when X..."
https://resources.allsetlearning.com/chinese/grammar/Expressing_%22when%22_using_%22dang%22

词汇
刻, a quarter of an hour (pinyin in tags)
https://mandarinbean.com/new-hsk-2-word-list/

Guardian:
当光线垂直射入镜面的时候, when light rays strike the mirror surface vertically
当你看到这封信的时候, when you saw this letter
[no 刻 of this kind]

Me:
当你去中国的时候，小心空气污染。
就算只是一刻，我也等不及了。

Comments

[grayswandir]

当光线垂直射入镜面的时候, when light rays strike the mirror surface vertically

I just looked this up out of curiosity, and I think 垂直 may mean "perpendicularly" here, since if I remember, the angle of the light in this episode is actually horizontal, hitting the mirror that's standing upright. (It's a new word to me either way!)

[nnozomi]

Thanks! Good point--I was careless. Looks like it can mean either one. I'm always fooled by 垂 which I know as meaning "to hang (ie hang straight down vertically)".

[grayswandir]

Yeah, I'd never heard it before, and the fact that it can mean horizontal as well depending on the context is rather confusing! Given the meaning of 垂, as you say, I'd assume "vertical" must have been the original meaning, and then I guess something hanging straight down is perpendicular to the surface of the ground...

[nnozomi]

"vertical" must have been the original meaning, and then I guess something hanging straight down is perpendicular to the surface of the ground...
Makes sense. That's an annoying double meaning, though...