You can set the fill style to be transparent or no fill. When object as no fill you will be able to see through the area of the object that is normally filled.
Note: if you set the fill style to be no fill or transparent make sure the object has a line or body style that is not transparent otherwise you will not be able to see the object. However, it will be selectable using the window select tool, you be will not be able to select it by clicking on it.
Click on the transparent button 
to set the fill style to transparent.
Transparent or no fill