Parallel structures are grammatical structures that use identical forms in a sentence. They are used with coordinating conjunctions like "and" and "but", correlative conjunctions like "not only...but also" and "either...or", and in comparative structures with words like "as" and "than". Examples include phrases like "to love and to be loved", "give me freedom or kill me", and comparisons involving identical parts of speech like "she has as many friends as I (do)". Parallel structures promote clarity and aesthetic impact in writing.

1. Parallel structures
Parallel structures are structures in which two or
more identical forms in grammar are used in a
sentence.
To love and to be loved are wonderful.
parallel

2. Parallel structures are used in the following cases:
1. With coordinating conjunctions
_____ and ____
_____ but ____
_____ or /nor ____
Give me freedom , or to kill / kill me .
Between you and I / me , I am right.
This life is short and full of sorrows.

3. 2. With correlative conjunctions
not only ____ but also _____
both _____ and _____
either _____ or _____
neither _____ nor _____
whether _____ or _____
She is not only pretty but also kind.
She likes both you and I / me .
He can’t decide whether to get a job or to go back to
school.
He can’t decide whether he’ll a job or go back to
school.

4. 3. With some comparison structures
She has as many friends in this city as I (do) / me.
She likes you more than me.
She likes you more than I .
It is better to have been loved and rejected than
not have been loved at all.