verb, noun, adverb · to serve as, act as, or manage a role or position

他在那家工厂当经理。

noun, verb, preposition · to treat as, replace, or think of something as being something else

他竟然把我的话当耳旁风。

preposition, particle, noun · at a certain time or place; during; on the spot

当他赶到火车站时，火车已经开了。

time word, verb, preposition · at or during (a certain time, period, or age), often used before a noun of time

他当少年时便立志报国。

numeral, verb · to be the same as or equivalent to; well-matched

他干起活来，一个人能当两个人使。

verb · ought to; used to express obligation or propriety

遇到不平的事，我们当挺身而出。

verb · to resist, obstruct, or match someone's power or force

这堵薄薄的墙当不住大风雪。

verb · to fail a student in an examination or course

他这学期被老师当了两科。

verb · to pledge an object as security for a loan

他把祖传的金表拿去当了。

adjective · suitable, adequate, fitting, or appropriate

如果处理得当，这些问题都能解决。

time word · at or in the very same time or place

该优惠活动仅在当周有效。