as we all know it是固定短语吗

As we are all know，failure is the mother of success．

Gunpowder，as we all know， was invented in ancient China.

as we all know为固定搭配，意为“众所周知”。

类似的固定词组搭配还有：

as we all know， as it is known， as is known to all等

如：

As is known to all， Mark Twain is a great American writer.全世界人都知道，马克·吐温是一位伟大的美国作家。

    

As we all know， the earth is round.众所周知，地球是圆的。（as在从句中作宾语）

   

 As is said above， we must protect our earth 就像上面说的一样，我们必须守护我们的地球。