"A veces nos sentimos mal en la noche."
Translation:Sometimes we feel bad at night.
Thanks for explanation re: action verbs and liniking verbs. I also initially thought this was supposed to be "badly" but I see the distinction now. I just said out loud to myself "I feel prettily" and it illustrates the point pretty well.
"At times we feel ill at night" and "Sometimes we feel ill at night" should be accepted. Reported July 2018.
I said, "We sometimes feel badly at night" and it was rejected. I've reported it.
In fact, the given translation is technically incorrect (although we often speak that way). The word following "feel" modifies the verb, so it is an adverb, and should be "badly". It's like the difference between saying "I feel good" (common, although technically incorrect) and saying "I feel well" (less common, but correct).
Actually, "feel badly" is incorrect unless you are saying that you are not good at touching or groping. When "feel" is an action verb (e.g., feeling a fuzzy peach), "badly" is correct, but when "feel" is a linking verb, describing emotion or state of being, you need to use an adjective--e.g., "I feel pretty".
If you can replace a verb with a form of "to be" and the sentence works, it's a sign that the verb you replaced was a linking verb. If we change "we feel bad" to "we are bad", it works grammatically. This means that "feel" is a linking verb in that sentence, and we need to use the adjective "bad".
If you don't believe me, you can consult grammar authorities on the internet.