The SAT and ACT exams test students on subject-verb agreement. In fact, 3.3% of the questions on these tests deal with subject-verb agreement. That means an average of 1-2 questions per SAT and 2-3 questions per ACT are on this concept.
When answering these types of questions, keep this in mind, nouns must agree with their corresponding verbs, and both need to be singular (referring to one thing) or plural (referring to more than one thing).
By far, the most common questions about subject-verb agreement separate the subject from the verb with other information.
The tricky part of the example is that the noun closest to the verb is the plural “friends,” so it may sound correct to say “friends are.” However, the thing that is part of the family tradition isn’t the friends but rather the “letter,” which is singular. Therefore, the corresponding verb should also be the singular “is.”
Some subject pronouns can be either singular or plural depending on the context of the sentence.
Clauses that begin with “which” often refer to the noun right before them, so the verb in that clause should agree with the corresponding noun.
Rarely, the subject follows the verb, especially in a question or when a sentence starts with a pronoun like “there,” “that,” or “it.”
Sometimes, a sentence or clause will have multiple subjects joined by a conjunction. When the conjunction is “and,” the verb should be plural; when it’s “or,” the verb should match the last noun.
When the subject is a title—as of a book—it’s always singular, even if the title refers to something plural.
Sometimes, a subject is word you wouldn’t normally think of as a noun, like the word “how.”
Understanding the different ways subject-verb agreement is tested will help you on both the SAT and ACT exams. To become more familiar with the different ways this rule shows up on the exams, it’s helpful to practice the same types of questions you will see on these tests. Use released exams provided by the College Board and ACT or practice online with exam-like questions at websites like UWorld.