Why would some of the subjects of pictures on your Canon Digital Rebel be out of focus?

You may have not allowed the camera time to focus. Press down and wait for the camera to focus before taking the picture. It may have focused on a subject in the foreground, thus causing a subject in the background to be out of focus. Read the owner's manual.
You may have not allowed the camera time to focus. Press down and wait for the camera to focus before taking the picture. It may have focused on a subject in the foreground, thus causing a subject in the background to be out of focus. Read the owner's manual.