The document describes common illnesses and diseases by defining key vocabulary words used to discuss pain and injuries in different parts of the body. It defines the words "ache", "pain", "hurt", and "sore" and provides examples of how to use each word as a noun, verb, or adjective when referring to physical sensations caused by illness or injury in parts like the head, back, elbow, knee, throat, and feelings. Activities are included asking the reader to make sample sentences applying the new vocabulary.