What fits best in this sentence and why
I feel bad or badly that Luis couldn't join us because of a bad case of summer flu.
Dos bad describe how I feel?
Yes, you're right. The correct word is "bad."
In this sentence, the word "badly" fits best. "Badly" is an adverb and is used to describe verbs, while "bad" is an adjective and is used to describe nouns/pronouns. In this sentence, the word is describing the verb "feel." Therefore, the correct way to express it is "I feel badly" because it is describing the manner in which you feel.
In this sentence, the word "bad" should be used to describe how you feel. The reason for this is that "bad" is an adjective, and it is used to describe nouns or pronouns. In this case, "bad" is describing the noun "I." Adjectives do not have an adverb form, so "badly" would not be the correct choice.
To determine whether to use an adjective or an adverb, you can consider the role of the word in the sentence. If the word is describing a noun or pronoun, an adjective is generally used. On the other hand, if the word is describing a verb, adjective, or another adverb, an adverb is usually used.
In this case, "bad" is describing how "I" feel, making it an adjective. So the correct choice is "bad" to describe how you feel in this sentence.