Completed Story:
Yesterday there was a party at my house. There were many friends there. I was very happy. There was a big cake and lots of balloons in the room. My best friend was on the table. We were at the party too. We were having fun.
Explanation:
- 1. there was: 'a party' is singular.
- 2. There were: 'many friends' is plural.
- 3. was: 'I' is singular.
- 4. There was: 'a big cake' is singular.
- 5. was: 'My best friend' is singular.
- 6. were: 'We' is plural.
- 7. were: 'We' is plural (used with the present participle 'having' to form the past continuous tense).