7. you (вы) having a Spanish lesson at 4 pm? — Yes, you / No, you

7. you (вы) having a Spanish lesson at 4 pm? — Yes, you / No, you

Согласно грамматике английского языка, необходимо вставить вспомогательный глагол перед подлежащим, чтобы образовать вопрос в Past Continuous (прошедшее продолженное время).

В данном случае, подлежащее - you, поэтому используем вспомогательный глагол were.

you having a Spanish lesson at 4 pm? - Were you having a Spanish lesson at 4 pm?

Yes, you / No, you - Yes, you were / No, you weren't.

Ответ: Were you (вы) having a Spanish lesson at 4 pm? — Yes, you were / No, you weren't