Just started learning Japanese again. My college offers no class on this so I am learning on my own. I have been using Rosetta Stone on and off again for a while now.

One thing I have noticed is that Rosetta Stone uses は and を in basic sentences such as:

>おんなのひとは、おちゃをのんでいます    

This sentence gives the Romaji:  

> onna no hito wa ocha o nonde imasu

Now I know

- は = ha  
- を = wo

Why would they use those in place of わ and お?