Irregular verbs are verbs that don’t follow the standard rule of adding -ed to form the past tense and past participle. Instead, they change in different ways or stay the same across tenses.

English has several ways to talk about the future, each with specific uses and meanings. The most common future forms are "will," "be going to," and the present continuous.

Relative clauses are used to give additional information about a noun in a sentence. They are introduced by relative pronouns like who, whom, whose, which, and that. Relative clauses make sentences more detailed and interesting by explaining or identifying the subject.

Reported speech, also called indirect speech, is used to describe what someone else has said, without quoting their exact words. It’s useful when recounting conversations or reporting messages.

Modal verbs are auxiliary (helping) verbs that express necessity, possibility, permission, ability, and more. They are used to modify the main verb in a sentence and provide additional meaning. Unlike regular verbs, modal verbs do not change form based on the subject.