My Mac Mouse has only a left button My Apple mouse has only one button (a Left button). Normally I use                   ctrl + left mouse as a way to use the left mouse button but it doesn't work with blender. what do I have to do. Because I can't select anything.
You can set selection to be with the left mouse button :


got to File➝User Preferences➝Input
in Select with click Left


also you can search and reassign all what is related to the right mouse button