What is the 4 kinds of simple sentence?

There are not exactly "4 kinds of simple sentences", but rather four main sentence structures that are considered simple sentences:

1. Declarative: These sentences make a statement. They tell you something.

* Example: The cat sat on the mat.

2. Interrogative: These sentences ask a question.

* Example: Did the cat sit on the mat?

3. Imperative: These sentences give a command or make a request.

* Example: Sit on the mat, cat.

4. Exclamatory: These sentences express strong emotion.

* Example: The cat sat on the mat!

It's important to note that a simple sentence is one independent clause, containing a subject and a verb, and expressing a complete thought. The sentence structure is what determines the kind of simple sentence.