After finishing the test, I checked my answers. Rule: Use a comma after an introductory phrase.

Although she was tired, she stayed up late to study. Rule: Use a comma after a dependent clause at the beginning of a sentence.

My teacher said, “You need to revise your essay.” Rule: Use a comma to introduce a direct quotation.

My brother, who lives in New York, is visiting this weekend. Rule: Use commas to set off nonessential (extra) information.

Before the game started, the players warmed up on the field. Rule: Use a comma after an introductory clause.

Students who study regularly perform better on tests. (No comma needed)Rule: Do not use commas with essential information (it defines which students).

I studied for hours, but I still felt unprepared. Rule: Use a comma before a coordinating conjunction (FANBOYS) when joining two complete sentences.

The movie was exciting; however, it was too long. Rule: Use a semicolon + comma with a conjunctive adverb (e.g., however, therefore).

We need to bring pencils, paper, and calculators to the exam. Rule: Use commas to separate items in a series (list).

In conclusion, students should prepare early for exams. Rule: Use a comma after introductory words/phrases (e.g., “In conclusion,” “However,”).