could for past possibility

[licinio]

Can I use "could" to express past possibility, such as in

A wasp could sometimes cause death in those days?

I'm asking because the answer sheet to an exercise only gave "would".

Thanks.

[5jj]

I'd prefer 'A wasp sting could sometimes cause death in those days' , but that's just being picky. 'Could' is fine; so is 'would', though the sentence then is rather more fatally definite.

[emsr2d2]

Can I use "could" to express past possibility, such as in

A wasp could sometimes cause death in those days?

I'm asking because the answer sheet to an exercise only gave "would".

Thanks.

"Could" is definitely possible here. I think "would" was probably given because wasp stings actually did sometimes cause death. I suppose that if you said "could", then it's possible that no-one ever died from a wasp sting but it was known that it was possible to be killed by one.