孙 (Sūn) is one of the most common Chinese surnames. It is historically associated with famous figures such as 孙子 (Sunzi, the military strategist) and 孙中山 (Sun Yat-sen). In texts, it often appears as a short form to refer to a person with this surname.
我们班有三个姓孙的同学。
wǒmen bān yǒu sān gè xìng sūn de tóngxué.
There are three students with the surname Sun in our class.
孙先生是这家公司的创始人。
sūn xiānshēng shì zhè jiā gōngsī de chuàngshǐrén.
Mr. Sun is the founder of this company.
大家都叫她小孙,她人很热心。
dàjiā dōu jiào tā xiǎo sūn, tā rén hěn rèxīn.
Everyone calls her Little Sun; she is very warm-hearted.