as you know係咩意思?

as you know = 如你所知的意思

eg. The target is hard to be achieved as you know.
如同你所知道的，這個目標是很難達到。
eg. He is so stubborn as you know.
如你所知的，他是一個很頑固的人。

as you know... = 你知啦......

example:
as you know, our business is under going a tough period. wonder if we can give you the pay cheque later?
你知啦.我地公司正值艱難嘅時候.唔知可唔可以遲啲先出糧比你?

as you know = 就像你明白的
The work is not so difficult as you know.
這工作不像你想像的那麼困難。