Parallel constructions comprise similar word or phrase patterns.
e.g The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates. The great teacher inspires. (William A. Ward) .
We see that the word "teacher" is repeated in every sentence. Besides, the verbs are used in the same tense form (Present Simple). These two factors (word repetition and tense coordination) make up for parallel structure / construction.
Efficient parallelism adds up rhythm and symmetry into the sentences as well as fills your writing with vigour. Parallel structures stress the similarity between several ideas.
Good parallel sentences are assets of any writing. Poor parallel sentences on the other hand only confuse your reader and inhibit understanding of your ideas. To make up a good parallel sentences observe the main rule of parallelism - grammatical elements of parallel construction must match. In faulty parallel sentences verb forms vary.
Compare: We can either stay here for a night or we're taking the first train to New York (poor parallel sentence, as the verb changes)
We can either stay here for a night or take the first train to New York. (Good - the verb tenses are coordinated).
Parallel sentences are especially efficient in thesis sentences. They allow you to integrate cohesively all the ideas of your argument:
"Because it humiliates children, it violates children's rights, and it causes children's violence, corporal punishment should not be used in schools."
The parallel construction makes your thesis clear and well-organized and it also shows the path to the three paragraphs you will be writing to back up your thesis.
You can use parallel structures with:
- Things in succession: We are bound by ideals that move us beyond our backgrounds, lift us above our interest, and teach us what it means to be citizens
- Paired items: Ask not what your country can do for you; ask what you can do for your country.
- Balanced Sentences: The mistakes of the fool are known to the world, but not to himself. The mistakes of the wise man are known to himself, but not to the world.