At a time in the past, especially the distant past.(adverb)
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Use "long ago" in a sentence
"Joseph John outgrew the classes at the Zion Academy long ago and had attended public school since he was twelve."
"She was one stern lady, a ranchwoman who had grown up in hard times, and all nonsense had long ago been washed out of her."
"But we had long ago rummaged through all of the drawers in the dressers and desks, finding scads of dried-out ink pens, paper clips, boxes of metal “I like Ike” buttons and a box of clear condoms that we used for a water-balloon battle."