know的过去分词是known，音标：英[nəʊn]；美 [noʊn]。短语：well known，众所周知的。例句：I've known David for 20 years. 我认识大卫已有20年了。

known 英 [nəʊn]  美 [noʊn] 
adj. 已知的；知名的；大家知道的
v. 知道（know的过去分词）

短语：

known as 被认为是，被称为；以…而著称

well known 众所周知的；出名的

known for 因…而闻名

best known 最著名的

例句：

1.He is little known as an artist. 

几乎没人知道他是个艺术家。

2.Christopher is commonly known as Kit. 

克里斯托弗通常被称为基特。

3.I wish we'd known about it beforehand. 

要是我们预先知道这事就好了。

4.Diamonds are the hardest known mineral. 

钻石是已知的最坚硬的矿石。

5.His views on the subject were well known. 

他对这个问题的看法众所周知。

6.Miriam Makeba became known as Mama Africa. 

米丽娅姆•马凯巴被称为“非洲之母”。

7.'Big Mac' is McDonald's best-known trademark. 

“巨无霸”是麦当劳最著名的商标。

8.He is known to have consorted with prostitutes. 

众所周知他曾与妓女厮混在一起。

9.The programme did much to popularize little-known writers. 

这个节目大力宣扬不太知名的作家。

10.She is known as a great beauty. 

她是个众所皆知的大美人。

11.The disease has no known cure. 

这种病目前还是不治之症。

12.I've known David for 20 years. 

我认识大卫已有20年了。

13.His books are not well known. 

他写的书不太有名。