1. Subject: This is the person, place, thing, or idea that the sentence is about. It's who or what is doing the action.
2. Verb: This is the action or state of being of the subject. It tells what the subject is doing or what is happening to the subject.
Additionally, a complete sentence should also:
* Express a complete thought: It should make sense on its own and not leave the reader wondering what happens next.
* Have correct grammar: This includes proper capitalization, punctuation, and word order.
Here are some examples:
* Subject + Verb: The dog barks.
* Subject + Verb + Object: The girl eats the apple.
* Subject + Linking Verb + Complement: The sky is blue.
Incomplete sentences (fragments) lack one or both of the essential components:
* The dog barking. (No verb)
* Eating the apple. (No subject)
Remember, every complete sentence should have a subject and a verb to express a complete thought and be grammatically correct.