HSK 7–9 grammar · conjunction
⋯⋯,乃至⋯⋯
⋯⋯,乃至⋯⋯ — and even, going as far as
Pattern
+ + +
( ) can be left out · other words may come before, between and after
How it works
乃至 extends a list to a final, more extreme member: "…and even…". It is formal and often widens the scale — from a city to a province to the whole country.
Examples
这项技术将影响本市乃至全国。
Zhè xiàng jìshù jiāng yǐngxiǎng běn shì nǎizhì quánguó.
This technology will affect the city and even the whole country.
几天乃至几个月都有可能。
Jǐ tiān nǎizhì jǐ ge yuè dōu yǒu kěnéng.
It could take days or even months.
Related
⋯⋯,甚至于⋯⋯ · ⋯⋯,甚至于⋯⋯ — even to the point of甚至 · 甚至 — even / to the point that⋯⋯,进而⋯⋯ · ⋯⋯,进而⋯⋯ — and then go on to

See it in a story
In the app, ⋯⋯,乃至⋯⋯ is underlined wherever it appears in the stories you read, and practised with sentences from them. Free.