What part of speech is 到 (to) when used in 两只饿到眼绿的老鼠正在房梁上打架?

Question

I was having trouble with the sentence

两只饿到眼绿的老鼠正在房梁上打架

because I could not understand the usage of 到 here. After I spent some time thinking I figure the meaning is that the rats were hungry to the extent that their eyes turned green (a metaphor of some sort?) but if that is indeed the case, what would you call this type of word? In English I believe the word "to" used in this way is called a preposition but I haven't seen anything online about the usage of prepositions in Chinese.

Answer 1

You are essentially correct. Here, 到 is a preposition that, depending on context, can represent "to," "(up) until," or "up to."

e.g. 到目前为止 : up until this moment

工作到天亮了 : work until the sky becomes light

从周一到周四 : From Monday to Thursday

In your particular example, there seems to be an implied “的程度" at the end of the descriptor which is omitted, i.e. one can write 两只饿到眼绿的程度的老鼠正在房染上打架, and in order to prevent a sentence from being clunky, this has been omitted since it's clear from context what is being said here.

Answer 2

I like that, "so hungry their eyes were green", haven't heard that before!

两只饿到眼绿的老鼠正在房梁上打架
2 hungry that eyes green 的 mice just in the room roof-beams fight
Two mice, both so hungry that their eyes were green, were fighting on a roof-beam.

Maybe it should be "饿的眼放绿光". Anyway, 饿到眼绿 means very very hungry.

饿到眼绿
hungry until eyes green 到 = until so hungry (their) eyes went green

"饿的眼放绿光"
hungry that eyes send out green light

A quick search gave me this answer. Not sure if it is accurate. I can't find a source for "饿的眼放绿光" . I'm sure someone here knows.

晚上狼的眼睛看起来是绿色的，说饿的眼放绿光，其实就是说饿得向狼一样，见到食物就像饿狼看见人一样。

Answer 3

Other examples I can think of:

红到发紫 --this is often used to describe someone is very popular

富到流油 -- this is used to describe someone is very rich

In all these cases, 到 can be replaced with 得.

To remember some use cases is a good way to remember how to use the word.