1. Commands are sentences that normally have no overt grammatical subject and whose verb is in the imperative form. There are 4 types of commands: without a subject, with a subject, with "let", and persuasive imperatives.
2. Exclamations are formal sentences that express emotions. They have short forms using "what" or "how" and long forms with additional elements. X-elements in exclamations can serve syntactic functions as subjects, objects, complements, or adverbs.
3. Concord is agreement between elements in sentences. Types of concord include subject-verb agreement in number and person, notional concord allowing plural verbs with collective nouns, and pronoun concord requiring agreement in number