Final answer:
The common nouns in the sentence are 'bands', 'festival', and 'park'. The noun 'band' can be used with singular or plural pronouns and verbs depending on whether the group acts as a single unit or not.
Step-by-step explanation:
Selecting all of the common nouns from the sentence provided, we have: "Bands play in Grant Park during the festival in June." The common nouns in this sentence are 'bands', 'festival', and 'park'. Note that these nouns are not specific names of unique entities, which would make them proper nouns, but they rather identify general items or concepts.
When it comes to collective nouns like 'band', pronoun agreement can be a bit tricky. The collective noun 'band' is often used with a singular pronoun as the group acts as a single unit, making it the most common construction. However, when the group members act individually, a plural pronoun may be more appropriate. It is also acceptable to make the plural form clear by using the word 'members' as in 'The band members loaded their instruments on the bus.' Whether to use a singular or plural verb depends on the context and how the group is acting.