[Grammar] played / was playing

[mihallure]

Can you please explain to me why can't we use both 'played' (as suggested in the Answer Key) and 'was playing' in the sentence below?

'She (to play) tennis when she was at university'.

Thank you!

 

[Matthew Wai]

"She was playing tennis when she was at universtiy."
Does the continuous tense mean that she was continously playing tennis all the time?

 

[mihallure]

"She was playing tennis when she was at universtiy."
Does the continuous tense mean that she was continously playing tennis all the time?

I wanted to use the continuous aspect because I thought it was a continuous action in the past, but the answer key indicated "played" as the only correct tense in this context.

 

[Matthew Wai]

I thought it was a continuous action

I think the action of playing tennis was occasional instead of continuous.

Not a teacher.