What is a subject noun?

A subject noun is the noun in a sentence that performs the action of the verb. It's the who or what that is doing something.

Here's how to identify it:

1. Find the verb: The verb is the action word in the sentence.

2. Ask "who" or "what" before the verb: The answer will be your subject noun.

Examples:

* The dog barked. ("Dog" is the subject noun because it's doing the action of "barking.")

* Sarah ate breakfast. ("Sarah" is the subject noun because she's eating breakfast.)

* The rain fell heavily. ("Rain" is the subject noun because it's falling.)

* The cat chased the mouse. ("Cat" is the subject noun because it's chasing the mouse.)

Important Note: Sometimes, the subject noun can be implied, rather than directly stated:

* Go to the store. (You are the implied subject noun performing the action "go.")

Let me know if you'd like more examples!