How do I delete table border ?

In my site homepage middle widget area, I want to make tables without border. As of now, you can see table border there, http://englishjump.net/.

The html code is

<table style="height: 30px;" width="570">
<tbody>
<tr>
<td style="text-align: center;">courses</td>
<td style="text-align: center;">courses</td>
<td style="text-align: center;">courses</td>
</tr>
</tbody>
</table>

1. How can I change the code above to delete border?
2. How can I set the width of each column at a fixed pixel? It means how I can make each cell have the same width whatever contents I enter into it.

Thank you

Jeonghun