This document provides grammar explanations about using forms of the verb "to be" in simple present tense. It discusses using "am" with "I", "is" with he/she/it and singular subjects, and "are" with we/you/they and plural subjects. It also covers forming contractions between pronouns and "am", "is", or "are", such as "I'm" and "she's", but not if the preceding word ends in certain letters. Examples are given to illustrate each rule.