original text
The ancients cast mirrors, large ones were flat, small ones were convex. Every concave is big and the convex is small. The small mirror can't see everyone's faces, so it is slightly convex and small, but the mirror is small and can accept everyone's faces ... This work is clever and intelligent, which can't be reached by future generations. Compared with the ancient lessons, they are all polished and leveled, which hurts Shi Kuang's bosom friend.
To annotate ...
Casting: manufacturing.
Jane: The mirror.
Then: just, then.
Order: let, let.
Micro: a little.
But, however, the tide turns.
M: Yes.
Bobby: Once.
Shi Kuang: A famous musician in the Spring and Autumn Period.
So: the reason ...
Therefore, therefore, therefore.
All: all, all
translate
When the ancients made mirrors, the big mirror was flat and the small mirror was convex. Concave mirror reflects a larger face image, while convex mirror reflects a smaller face image. So make it slightly convex to make the face smaller, so that even if the mirror is small, it can still capture the whole face ... This craft is ingenious, and later people can't do it. Once you get the ancient mirror, you should scrape it smooth. This is why Shi Kuang (a famous musician in the Spring and Autumn Period) is very sad, and no one really knows the melody!