Parallelism (also known as Parallel Structure) means having a grammatical balance between related ideas in a sentence. You will often write a sentence that contains two or more points (examples, details, etc); in this case, these similar ideas must be the same grammatical structure. In other words, nouns should be paired with nouns, verbs with verbs, phrases with phrases and so on.
Not Parallel:
- International students sometimes have difficulty academically, financially, and they find it hard to meet people.
- When addressing the audience, he spoke sincerely and with passion.
Parallel:
- International students sometimes have difficulty academically, financially and socially.
- When addressing the audience, he spoke sincerely and passionately.
Remember that you have lots of choice when writing a sentence in a parallel form. The key is to be consistent.
All of these sentences are parallel:
- When addressing the audience, he spoke sincerely and passionately.
- When addressing the audience, he spoke with sincerity and passion.
- When addressing the audience, he spoke with sincerity and with passion.