shéi
你找谁？
nǐ zhǎo shéi?
Who are you looking for?
今天谁值日？注意“谁”可以指一个人或几个人，方言中有用“谁们”表示复数的。有时叠用，表示无须说出的某人的名字，如：乡亲们传说着谁谁立了大功，谁谁当了英雄。
Jīntiān shéi zhírì? Zhùyì "shéi" kěyǐ zhǐ yī gè rén huò jǐ gè rén, fāngyán zhōng yǒu yòng "shéimen" biǎoshì fùshù de. Yǒushí diéyòng, biǎoshì wúxū shuō chū de mǒu rén de míngzì, rú: Xiāngqīnmen chuánshuō zhe shéi shéi lìle dàgōng, shéi shéi dāngle yīngxióng.
Who is on duty today? Note that "who" can refer to one person or several people. In dialects, "shéimen" is used to indicate plural. Sometimes it's repeated to represent someone's name that doesn't need to be mentioned, for example: The villagers spread stories about so-and-so who achieved great merit, and so-and-so who became a hero.
谁不说他好。注意反问句中用“谁知道”有时候是“不料”的意思：我本是跟他开玩笑，谁知道他真急了。
Shéi bù shuō tā hǎo. Zhùyì fǎnwèn jù zhōng yòng "shéi zhīdào" yǒushíhou shì "bùliào" de yìsi: Wǒ běn shì gēn tā kāi wánxiào, shéi zhīdào tā zhēn jíle.
Who doesn't say he's good? Note that in rhetorical questions, "who knows" sometimes means "unexpectedly": I was just joking with him, who knew he would actually get angry.