PC versus Imparfait

Question

Why is is imparfait used in this sentence?  L'écureuil allait plus vite que lui...  I would have considered the phrase  part of the story chronology-- not background/description.  Or should I "translate" it as The squirrel was faster than him...  since it is a comparison of speed?  Merci?

Accepted Answer

Hi White,
The sentence -
...l'écureuil allait plus vite que lui...
could be translated as 
the squirrel was going faster than him
or 
the squirrel was faster than him
but the imperfect is correct here and you can see the squirrel running in continuing action.
Hope this helps!

Answer

Is it in the imparfait because it is desciption of continuous action that had not ended at that time ? I find this a very confusing topic.