A series has three or more parts one after the other. 

The parts of a series can all be single words.

milk, bread, and eggs

The parts of a series can all be phrases.

to go to the bank, to talk to the doctor, and to meet a friend

The parts of a series can all be short sentences (complete ideas).

He wrote a letter, he cleaned the house, and he fed the horses.

 All three kinds of series use commas between the parts.  If a series is longer than three parts, it will need more commas to separate the parts.

Add commas to the following series, if necessary.  Check your answers once you finish.

1. The tractor ran away through the meadow across the stream and up the hill.

ANSWER The tractor ran away through the meadow, across the stream, and up the hill.

2. John Mary and Philip were kept after school because they put glue on the teacher’s eraser.

ANSWER John, Mary, and Philip were kept after school because they put glue on the teacher's eraser.  

3. April and May are my favorite months of the year.

ANSWER No commas needed. There are only two parts here.  

4. She went to town to buy groceries to pick up her pay check and to see the doctor.

ANSWER She went to town to buy groceries, to pick up her pay check, and to see the doctor.  

5. Andy had a fight with John and Peter.

ANSWER No commas needed. There are only two parts here.  

6. She washed her face brushed her teeth and went to bed.

ANSWER She washed her face, brushed her teeth, and went to bed.  

7. Bob is afraid of three things: spiders dogs and snakes.

ANSWER Bob is afraid of three things: spiders, dogs, and snakes.  

8. Riding horses and swimming in the lake are her favorite activities.

  ANSWER No commas needed. There are only two parts here.

9. The old man the young lady and the little baby all got into the old truck.

  ANSWER The old man, the young lady, and the little baby all got in the old truck.

10. Both iced tea and iced coffee are refreshing drinks.

ANSWER No commas needed. There are only two parts here.