In non-Euclidean geometry there are no parallel lines, but there should be 'parallelism' in your English sentence.

Parallel structure is a grammatical construction in which two or more items in a sentence have the same grammatical form. The purpose of parallel structure is to create balance and clarity in writing or speaking.

Common mistakes even some native speakers make when using parallel structure include:

1. Failing to maintain consistent grammatical form, such as mixing verb tenses or using different parts of speech for parallel items.
2. Failing to properly structure parallel items, such as not using a coordinating conjunction between them or using too many conjunctions.
3. Failing to recognize when parallel structure is needed, resulting in awkward or unclear phrasing.

Here are some examples of incorrect usage of parallel structure:

Incorrect: I like to hike, swimming, and to ride a bike. Correct: I like to hike, swim, and ride a bike.

Explanation: The verbs "hike," "swim," and "ride" are not in the same form. To make them parallel, we need to remove the "to" before "swim" and "ride."

Incorrect: The new employee was expected to be punctual, to have a positive attitude, and is a team player. Correct: The new employee was expected to be punctual, to have a positive attitude, and to be a team player.

Explanation: The third item in the list should be in the same form as the first two. To make it parallel, we need to add the infinitive "to be" before "a team player."

Incorrect: The students were asked to write an essay that was clear, concise, and to make it informative. Correct: The students were asked to write an essay that was clear, concise, and informative.

Explanation: The phrase "to make it" is unnecessary and breaks the parallel structure. We can remove it to make the items parallel.

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