"En ce temps-là, nous achetions souvent des choses inutiles."

Translation: At that time, we would often buy useless things.

[AronTrinidad]

I found this in Past Imperfect Level 0, 5/5. I thought « achetions » was something like "used to buy" or "bought", but no, it was "would buy". Any reason why this is in Past Imperfect?

[Bob_Bowes]

A habit or repeated action 'would often buy

[mng22]

I was marked correct, but cautioned
"You have an extra space.
At that time we were oftenbuying useless things."
It wanted me to leave out the space between "often" and "buying". I could not report, as there wasn't a relevant option to check off.

[biscuitamericain]

''in those days we often bought some useless things''...I do not understand why this is wrong