Simple past tense and past participle of alternate.(verb)
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Use "alternated" in a sentence
"The first 32 issues featured Lee Falk's The Phantom stories, but thereafter, the title alternated between various King Features characters, including Mandrake, Flash Gordon, and Buz Sawyer."
"The other evening the clergyman dined with us, and throughout the meal discussions of the rubric alternated with talk about delicacies of the table!"
"A glance back showed Barriss hanging on for dear life, while Anakin's expression alternated between grim determination and youthful alarm."