Fill in the gaps: - Where _____ you yesterday? - I _____ in the swimming pool.

Let's fill in the gaps with the correct forms of the verb "to be" in the past tense.

The first sentence is "Where _____ you yesterday?". Since "you" is plural, we use "were". So the complete sentence is: "Where were you yesterday?"

The second sentence is "I _____ in the swimming pool." Since "I" is singular, we use "was". So the complete sentence is: "I was in the swimming pool."