Answer:
The best revision of the modifier in sentence 5 is to use bad instead of badly.
Step-by-step explanation:
The adjective bad should be used instead of the adverb badly because feel is a copulative verb. A copulative verb shows no action, it links the subject to an adjective or to another noun. All the verbs denoting the five senses are linking verbs: taste, look, sound, feel, and smell. Therefore, the revised version of the sentence would be as follows: She felt bad that someone had lost such a nice watch.