know hawk from a handsaw

普通识别力；有一般的鉴识力。

know a thing or two (know how many beans make five)

【口】非常精明；非常老练。

know about

了解。

know all the answers

(非正式用法)【贬】万事通。

know sb backwards (and forwards)

对...十分清楚；彻底了解。

know better (than)

不致于笨到做...；知道(某事)是不对的。

know by sight

认得(某人)面识。

know enough to come in out of the rain

有判断力；能照顾自己。

know if (whether) one is coming or going

思虑清晰；应付自如。

know (feel) in one's bones

预感；直觉感到。

know inside out

【口】十分熟悉。

know of

知道...的存在(情形)。

know (on) which side one's bread is buttered

知一己利益之所在。

know one's business

有见识；精明能干。

know one's own mind

有主见的。

know one's place

懂分寸(指下级对上级)。

know one's way around (about)

(对某行业)很内行；(对世事)有经验；老练。

know the ropes

【口】懂得诀窍；熟悉内情。

know the score

【美】【口】知悉实情，真相(特别指不利的情况)。

know the time of day

【口】明事理。

know what is what

深知底细；老成练达。

know what one is about

非常精明机敏；处事周详。

know where the shoe pinches

知问题的症结所在。

all one knows

全力；尽可能。

and I don't know what (who) (else)

【口】各式各样的事物(人)(用于举例说明后的结语)。

before one knows where one is

【口】来不及思考地；无意中地。

for all I know

就我所知。

I don't know from nothing (about it).

【美】【口】我什么都不知道。

not know sb from Adam

对某人全然不认识(尤指对男人)。

not know one is born

【口】过舒适生活(尤指与以前比较)。

not know one's arse from one's elbow

【俚】【贬】没见识；一无所知。

not know where to put oneself (one's face)

【口】心里不舒服，窘困。

not know which way to turn (jump)

束手无策。

not that I know of

【口】据我所知并非那样。

you know

你知道的(强调语气用)；听着！记住！(用于提醒某人)。

in the know

熟悉内情。