Решение:
Используем 'was' для I, he, she, it; 'were' для you, we, they.
- I was at school yesterday.
- They were in the park last Sunday.
- She was happy because she got a gift.
- We were tired after the long walk.
- The cat was on the sofa.
- You were late for the lesson.
Ответ: 1. was, 2. were, 3. was, 4. were, 5. was, 6. were.