Select tool and Faces
 

I have a question ..

how can i delete all the Faces the front and the back faces with selection tool

when i use select toll to select cube faces and i hit [Delete]
i found not all faces is select ?

please see this video to know what i mean ..

http://www.youtube.com/watch?v=fAQY5...e=channel_page

hmm, that's a weird one. It doesn't look like you have backface culling on and it looks like your orthographic view's settings are short-cutting the geometry to prevent selecting it. Maybe try changing the selection settings to selecting faces with the selection handle rather than the entire face will help?