源遠流長 [ㄩㄢˊ ㄩㄢˇ ㄌㄧㄡˊ ㄔㄤˊ; yuan2 yuan3 liu2 chang2] lit. source is distant and the flow is long (idiom); fig. sth goes back to the dim and distant past a lot of water has flowed under the bridge since then ◄ ►
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