(informal)be a serious matter or difficult undertaking
(非正式)嚴(yán)肅的事；不輕松的事；困難的事
trying to shop with three children in tow is no joke.
要帶著三個孩子去買東西可不是件輕松的事。
(informal)become (or be) something that is serious or worrying
(非正式)（變成）嚴(yán)肅的事，令人擔(dān)心的事
this rain's getting beyond a joke.
這場雨越來越讓人擔(dān)心了。
laugh or be humorous about (something that is not funny in itself)
對（并不好笑的事）以笑（或幽默地）對待，一笑置之