Does it match?
Sometimes the student is asked to do a slow check as a means of checking and correcting a word. The student slides a finger under the word as he slowly says it. The purpose is to notice if the look and the sound of the word matches.
This is something you can try at home after a word is incorrectly read. Have your child slide her finger under the word in the book as she slowly says it. You may have to say the word as well, and emphasize the sounds that do not match, before a mismatch is noticed by your child. (Do not confuse your child by doing this with a word that does not sound like it looks!)