que vs lo que - further explanation needed

Question

Hello, Can anyone explain (without guessing) why one of these sentences has 'lo que' and the others only have 'que' - when in english, they all 3 include "know what".

* Sabes lo que tienes qué decir. You know what you have to/must say.
* Ya sabes qué decir. You already know what to say.
* Sabes qué decir. You know what to say.

Answer 1

Hi erin, you are welcome to ask the question in your former post, just post it there, thanks.