Parallelism means using a similar structure throughout a sentence. Parallelism makes sentences clearer and easier to read. It balances your writing and makes it more effective.

Incorrect: She enjoys reading, listening to music, and to play the guitar
Correct: She enjoys reading, listening to music, and playing the guitar.

Ending all the verbs in the list with -ing is one example of parallelism.

Using parallelism makes your writing flow more naturally. It also gives equal importance to elements of a sentence. When sentences do not have parallel structure, it is called faulty parallelism.

Let's take a look at a few more examples.

Incorrect: He walks the line and knew that he had won.
Correct: He walks the line and knows that he had won.

Incorrect: I like to play video games, reading, and baking.
Correct: I like playing video games, reading, and baking.

Incorrect: She went to London, Paris, and then to Rome.
Correct: She went to London, to Paris, and then to Rome.
Correct: She went to London, Paris, and then Rome.

Incorrect: The dog is either in the crate, the bedroom, or backyard.
Correct: The dog is either in the crate, the bedroom, or the backyard.
Correct: The dog is either in the crate, bedroom, or backyard.

Incorrect: He ran to the store and had bought a pie.
Correct: He ran to the store and bought a pie.

Incorrect: They offer degrees in philosophy, engineering, and becoming a social worker.
Correct: They offer degrees in philosophy, engineering, and social work.