Question

【题目】They prepared the food just now. (改为否定旬)
They the food just now.

Answer 1

【答案】didn't；prepare
【解析】根据prepared句子时态是一般过去时，谓语动词是行为动词，变否定句时借助于didn't,谓语动词用原形，所以答案是：didn't prepare。