To the extent that forms of deber are translatable as "should", "ought" should also be an option. Or, perhaps, it must also be an option? Or ought to also be an option? :-)
In terms of the etymology, deber comes from the same Latin root as the modern accounting word "debit". It means "to owe". English "ought", being a form of "to owe", is arguably the closest translation.
They are similar, but not exactly the same. «Debo» = I must, «Tengo que» = I have to.
For the most part, «debo» is self imposed, while «tengo que» is externally imposed. It can be tricky since sometimes the lines are blurred in both languages for effect, but it's not the norm.
- Estoy gordo, no debo comer más dulces si quiero bajar de peso. (Self imposed)
- Estoy gordo, tengo que bajar de peso para ingresar al ejército. (Externally imposed)
Debería is conditional where debe isn't. Think of debe as a self-command: I MUST. Debería is more of a suggestion: I OUGHT to or I'd better do something. Honestly though, I don't hear deber a lot on conversation and kind of disagree with duolingo's emphasis and translation of deber.
Take only something like "I should run" and remember that in English English at least, context becomes important.
It can be used when you are in a hurry and speaking to a friend and say "I should run", you may mean you have to catch a train or whatever, or it could be "I should run" (because I need to lose weight), context will dictate the meaning.
In the same way, "must" is exactly the same, except in English it would indicate more of an urgency or necessity generally. "I must run" (because the Doctor says I HAVE to or else) or "I must run" (because if I don't go NOW, I will really miss the train)
Could just be another example of Duo the owl and perhaps American vs English English, who knows?
I went for "I will run" as well, but I have noticed "shall" being used in some DL options - I haven't heard anyone under 70 years of age use shall as a word in many years - it's amost disappeared along with forsooth and gadzooks in common use. 2c worth, since DL seems to be American in origin judging from the spelling mistakes - ooops - differences, so that may account for some answers?
Yes and no.
Yes in the sense that if the correct translation were actually what Duolingo has, "I ought to run" should be acceptable too.
However, the correct translation of «Debo correr» is actually "I must run". I should (ought to) run is «Debería correr».
The reason is that just like "must" is not the same as "should/ought" in English, «debo» is not the same as «debería» in Spanish. They have the same distinctions.
Unfortunately, this is an incredibly common mistake in most learning platforms and materials I've seen and it leads to all manner of confusion.
Adrianauna, as in all things DuoLingo, it's not what you or I or anyone else uses that is a "correct" answer, it's the answer that DL wants you, I and everyone else to actually give.
And that's life! (I have a wee notebook that I write these things down in when I come across them, "1" - it reinforces it for the next time, and "2" - keeps the streak going.
Have a Lingot on me for the question!
or my wee musings and occasional thoughts