(classical particle similar to 於|于[yu2]) in / at / from / because / than / (classical final particle similar to 嗎|吗[ma5], 吧[ba5], 呢[ne5], expressing question, doubt or astonishment)
(after a verb or adjective) one who (is) ... / (after a noun) person involved in ... / -er / -ist / (used after a number or 後|后[hou4] or 前[qian2] to refer to sth mentioned previously) / (used after a term, to mark a pause before defining the term) / (old) (used at the end of a command) / (old) this