n (1)线索(sth (such as fact，evidence，information，object，etc)that helps to find an answer to a problem or mystery)[C][N(to)]：The car number/footprint/fingerprint was a～to the identity of the murderer.汽车号码/脚印/指纹是查明凶手身份的线索。have/find/leave no～s as to who murdered sb没有/没找到/没留下行凶者的线索;The～to solving the energy problem lies in conservation.解决能源问题的答案在于资源保护。〖同〗sign，hint，trace，indication，evidence，mark，key;

(2)填字游戏中要填的字(word or words that help(s) to solve a crossword puzzle)[C]：I can't do/answer the third～in the crossword.我做不出这填字游戏中的第三个字。

not have a clue (infml) 1)一无所知;不知如何做某事：He hasn't a～about modern art.他对现代艺术一无所知。She doesn't have a～about how to change the wheel of a car.她根本不知道怎么换车轮。2)愚蠢，无能(derog)：Don't ask him to do it — he hasn't a～.别求他干这事——他没这本事。

→′clueless adj 愚蠢的，无能的;

v

clue up (about/on sth)(v adv)熟知(vt)(通常 pass)(infml)：He's really/very～d up on/about modern painting.他通晓现代绘画。

clue in (on sth)(v adv)提示(vt)(infml)：～sb in on the latest developments让某人了解事态的最新发展