Explanation

The subject is who or what the sentence is about – who performs the action (or exists/is described). Find it by asking “Who/what + verb?”

Simple subject: main noun/pronoun. Complete subject: simple subject + modifiers. “The tall student in the blue shirt ran” – simple subject is “student,” complete subject is “The tall student in the blue shirt.”

Tricky cases: inverted sentences (verb before subject), commands (implied “you”), there/here constructions (subject comes after verb).