AI Tutor
Take a look at this sentence: After eating the dog wanted to go outside. Did someone actually just eat a dog?
A single misplaced pause changes the entire scene. When we add a comma—After eating, the dog wanted to go outside—the confusion vanishes.

Introductory Elements

An introductory element is a word, phrase, or dependent clause that gives background information—like when, where, or how—before the main action begins.
Because it cannot stand alone as a complete sentence, we use an introductory comma to separate this runway from the main runway.
Look at this worked example: Although it was raining hard, the soccer team finished practice.
If you strip away Although it was raining hard, the leftover thought—the soccer team finished practice—stands perfectly on its own two feet.
A common trap is adding a comma after every single opening word. A brief prepositional phrase like In 2024 we moved does not require a comma unless leaving it out causes a reader to stumble.
So introductory pieces set the stage at the front—but what happens when extra information drops right into the middle of your sentence?

Parenthetical Clauses and Interrupters

A parenthetical clause is extra side information tucked inside a sentence that can be removed without breaking the grammar or changing the basic fact.
Think of parenthetical commas like a pair of handles: you must place one comma before the interrupter and one comma after it to safely lift it out.