英语提建议的句型

Why don't you...
Why not...

will you do .......
would you like do ......
you should do .......

why not 。。。？为什不。。。呢？
You'd better (not) do sth. 你最好（不）做某事
why don't you do sth? 你为什么不。。。？
advise sb (not) to do sth 劝告某人（不）做某事
Let sb do sth 让某人做某事
What do you think of doing sth? 你认为做某事。。。。？

If you do .......it will be better

It is recommended to do sth.
这是比较婉转的提建议的方式，而且采用形式主语被动态可以弱化主观色彩。

I suggest you do sth.
I advise you do sth.