GMAT Sentence Correction (SC) | Re: The British sociologist and activist Barbara Wootton once

Suppose an action (action1) took place at a particular time in the past. Suppose another action ( action 2) was happeningin the background when action 1 took place, i.e. action 2 started before action 1 took place, action 2 was simultaneously happening when action 1 took place and action 2 continued to happen for some time after action 1 took place.

In such case, action 1 is depicted by simple past and action 2 is depicted by past continuous. e.g.:

The
...

---