1.Jack of all trades and master of none.
门门精通，样样稀松。

2.Judge not from appearances.
人不可貌相，海不可斗量。

3.Justice has long arms.
天网恢恢，疏而不漏。

4.Keep good men company and you shall be of the number.
近朱者赤，近墨者黑。

5.Kill two birds with one stone.
一箭双雕。

6.Kings go mad, and the people suffer for it.
君王发狂，百姓遭殃。

7.Kings have long arms.
普天之下，莫非王土。

8.Knowledge is power.
知识就是力量。

9.Knowledge makes humble, ignorance makes proud.
博学使人谦逊，无知使人骄傲。

10.Learn and live.
活着，为了学习。

11.Learning makes a good man better and ill man worse.
好人越学越好，坏人越学越坏。

12.Learn not and know not.
不学无术。

13.Learn to walk before you run.
先学走，再学跑。

14.Let bygones be bygones.
过去的就让它过去吧。

15.Let sleeping dogs lie.
别惹麻烦。

16.Let the cat out of the bag.
泄漏天机。

17.Lies can never changes fact.
谎言终究是谎言。

18.Lies have short legs.
谎言站不长。

19.Life is but a span.
人生苦短。

20.Life is half spent before we know what it is.
人过半生，方知天命。