Learn Spanish (Spain): Mi abuela tenía un oficio muy duro. - My grandmother had a very hard trade.

In Spanish, the imperfect tense is used to describe continuous states or background situations in the past. Having a job is an ongoing state, not a single, sudden event. If you used tuvo, it would sound like a one-time event, such as the exact moment she got the job, or a completed action with a specific, closed start and end date.

Oficio looks a lot like "office". Does it mean she worked in an office?

No, this is a classic "false friend"! The Spanish word for "office" is oficina. An oficio is a trade, craft, or profession, usually referring to manual or skilled labor (like being a carpenter, baker, or seamstress).

Could I just say un trabajo muy duro instead of un oficio?

Yes, you absolutely could! Trabajo means "job" or "work" in a general sense and is completely fine here. Oficio is just a bit more specific, emphasizing that her job was a distinct trade or craft rather than general employment.

Can duro mean "difficult" as well as physically "hard"?

Yes! Just like in English, duro can describe an object that is physically hard (like a rock), but it is also widely used to describe situations, tasks, or jobs that are tough, exhausting, or demanding.