Краткое пояснение: Выбираем правильную форму глагола to be (was/were) в зависимости от числа подлежащего.
Решение:
- My friends and I were at the beach on Saturday.
- I was in bed at ten o'clock.
- My cat was in the tree.
- The mice were in the kitchen.
- The women were at the museum.
- The man was at the swimming pool.