7. I couldn’t recognize the melody that _____. a) is being played; b) was being played; c) has been played; d) had been played.

Перевод задания: Я не мог узнать мелодию, которая _____.

Действие происходило одновременно с тем, что я не мог узнать мелодию, поэтому подходит Past Continuous Passive: was being played.

I couldn’t recognize the melody that was being played.

Я не мог узнать мелодию, которая играла.

Ответ: b) was being played.