Here are the suggested fillings for the blanks using "was/ wasn't/ were/ weren't/ did/ didn't":

1. **Did** you start a community garden project last month?
2. Last week, we (not) **didn't** visit sick children in Viet Duc Hospital.
3. **Was** there anything that made you happy with your work last month?
4. It **wasn't** Tom's fault. It's mine.
5. What **did** you do in the summer?
6. **Did** she visit Hue when she was a child?
7. Mimi and Lucy **were** at home in Florida last week. We were at Ben’s house in Miami.
8. He (not) **didn't** come to the party last Sunday.
9. Julia (not) **didn't** wear uniform to school yesterday.
10. **Is** John at work today? — "No, he **isn't** in the office. I think he's sick."