Subject-Complement Agreement? P or S?

Test Preparation SAT Preparation
1

<p>At the reception were the chattering guests, the three-tiered cake, and the lively music that have become characteristic of many wedding celebrations. No error</p>

<p>Answer: No error
Explanation for Incorrect Answer D :
There is no error at (D). The subject complement “characteristic” idiomatically follows the linking verb phrase “have become” and appropriately describes the subjects. The preposition “of” idiomatically follows the adjective “characteristic” and appropriately introduces the prepositional phrase “of many wedding celebrations.”</p>

<p>My Question: The CB explanation of why D is correct confuses me. Shouldn't the complement "characteristic" be plural since it describes the subjects? So, shouldn't the corrected sentence read: "characteristics of..."</p>

2

<p>I remember this question. Originally I thought it would be plural too, but really it’s just an idiom. It doesn’t follow the normal s/p rules because the idiom is “characteristic of”.</p>

3

<p>But “characteristics of” is a proper idiom. </p>

<p>ex: what are the characteristics of a mouse?</p>