Commas are used in writing to indicate a pause, separate items in a list, clarify meaning, or indicate a nonessential element in a sentence. Here are some examples of situations where commas are commonly used:

1. To separate items in a list:
   • I need to buy milk, eggs, bread, and butter.
   • The colors of the flag are red, white, and blue.
   • She enjoys playing soccer, basketball, tennis, swimming, and volleyball.
   • He packed his bag with clothes, shoes, toiletries, and books.
   • The recipe requires sugar, flour, eggs, milk, and vanilla extract.
2. To separate independent clauses in a compound sentence:
   • I finished my work, and then I went for a walk.
   • She loves to sing, but she doesn’t like to dance.
   • He studied hard, so he aced the exam.
   • They planned the event, and they invited all their friends.
   • She went to the store, and she bought some groceries.
3. To set off introductory phrases or clauses:
   • In the morning, I like to have a cup of coffee.
   • After finishing dinner, we went to see a movie.
   • With great excitement, she opened the gift.
   • On a sunny day, the beach is the perfect place to relax.
   • As I was walking down the street, I saw an old friend.
4. To separate nonessential elements or additional information:
   • John, my brother, is a talented musician.
   • The movie, which was released last month, received positive reviews.
   • The car, a sleek sports car, caught everyone’s attention.
   • The dog, named Max, loves to play fetch.
   • My favorite book, Pride and Prejudice, is a classic novel.
5. To separate adjectives when they modify the same noun:
   • She wore a long, flowing dress to the party.
   • He is a smart, kind, and funny person.
   • The old, wooden table creaked as we sat down.
   • She lives in a small, cozy cottage by the lake.
   • The delicious, homemade cake was a hit at the party.