5. We laughed a lot last Sunday. 6. Vova danced in his dream. 7. I joined a sports centre two days ago.

Решение:

Задание требует преобразовать утвердительные предложения в отрицательные, используя вспомогательный глагол 'did' и частицу 'not' перед смысловым глаголом в его базовой форме (инфинитив без 'to').

• 5. We laughed a lot last Sunday. — We didn't laugh a lot last Sunday.
• 6. Vova danced in his dream. — Vova didn't dance in his dream.
• 7. I joined a sports centre two days ago. — I didn't join a sports centre two days ago.

Ответ: 5. didn't laugh, 6. didn't dance, 7. didn't join