Natural Chinese > courses > Character Video Database > Nouns: > Numbers/数字 > 一(yī)

一: 十一,一个人,….

usage:

一+measure word:When 一 is followed by a forth-tone character, 一 is usually pronounced as second tone, for example: 一个 , 一次.

in other cases, 一 is pronounced as fourth tone, for example: 一杯,一张,一种,一瓶,一把,一直, ….