Put the verbs in brackets into the past simple or past continuous. 7 While I (listen) to music, I (hear) the doorbell.

While I **was listening** to music, I **heard** the doorbell.
Explanation: The action of listening to music was in progress when she heard the doorbell, so we use the past continuous for listening ('was listening'). Hearing is a completed action, so it's in the past simple ('heard').