The consistent use of the same verb form or tense in a single sentence

Verb tense consistency refers to keeping the same tense throughout a clause. You don't want to have one time period being described in two different tenses. If you have two or more time periods, start a new clause or a new sentence.

right angles are formed by perpendicular lines. if the lines would extend, to make two intersecting lines, they would form four right angles.

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