while I was reading / sleeping

Grammar notes

While Builds the Background

Use while to show the longer action in progress. The other action is often in the past simple. While helps the sentence feel like a full scene, not just a single moment.

• Example: While I was reading, Tom knocked on the door.
• Example: While they were sleeping, the storm started.

Quick Rule

• while + past continuous for the background action
• use past simple for the shorter interrupting action

Think of while as the word that keeps the background open.