how can i correct this sentece to parallel structute? When the movie Star Wars premiered in 1977, it was both surprising and a revolution in its special effects.

This is the problem area in that sentence:

... it was both surprising and a revolution in its special effects.

surprising = participle, serving as an adjective
revolution = noun

You'll need to make them both adjectives or both nouns. There is no one right answer! Give it a try, and I'll check your work for you.

To correct the sentence and achieve parallel structure, you can rephrase it as follows:

"When the movie Star Wars premiered in 1977, it was surprising and revolutionary in its special effects."

Explanation:
Parallel structure refers to using similar grammatical forms in a sentence, particularly when listing or comparing items. In the original sentence, "surprising" and "a revolution" are not parallel because they differ in grammatical structure. By changing "a revolution" to "revolutionary," both terms become adjectives and have the same grammatical structure.