Question

"When you phoned, I was having dinner"

transforme em negativo e interrogativo

N:

I:​

Answer 1

Resposta:

N: When you phoned, I WASN'T having dinner

Só adicionamos o "not" e juntamos com o "was" (wasn't)

I: Was I having dinner when you called?

Trocamos o "Was" e o "I" de lugar e botamos no ínicio da frase