The document discusses the different tenses in English grammar. It defines tense as the change in verb form according to when an action occurs. There are 16 tenses total divided into present, past, and future categories. The present simple tense is described in detail, including its patterns for subject-verb agreement and examples of affirmative, negative, and interrogative sentences. The uses of the present tense include describing general truths and habits. Spelling rules are provided for the third-person singular form, and notes are made about adverbs of frequency and modal auxiliaries.