Rule 1. A subject will come before a phrase beginning with of. This is a key rule for understanding subjects. The word of is the culprit in many, perhaps most, subject-verb mistakes.
A bouquet of yellow roses lends color and fragrance to the room.
Rule 2. Two singular subjects connected by or, either/or, or neither/nor require a singular verb.
My aunt or my uncle is arriving by train today.
Explanation:
a wide scattering of people who lived near rivers in temporary settlements of 1-3 households and practiced a mixture of hunting, gathering and crop growing
The correct answer is The dance committee hung the decorations—blue and gold streamers—on the morning of prom.
Explanation:
The original sentence is incorrect in terms of punctuation because an essential detail that belongs to the main sentence "the decorations" has been enclosed in parentheses. This is an incorrect use of the parentheses because these and the em dashes (—) enclose additional details. In this context, to correct the punctuation the parentheses should be omitted. On the other hand, the em dashes enclosing the detail "blue and gold streamers" are correct because this an additional non-essential detail.
