There are four main types of sentences based on their purpose: declarative, interrogative, imperative, and exclamatory. A declarative sentence makes a statement and ends with a period, such as “She is studying.” An interrogative sentence asks a question and ends with a question mark, like “Are you coming?” An imperative sentence gives a command or request, for example, “Please sit down.” An exclamatory sentence expresses strong emotion and ends with an exclamation mark, such as “What a beautiful day!” .