The subject of the sentence, "Early education programs," is plural, but the verb that refers to it, "has been shown," agrees with a singular subject. It can be easy to miss this because of the interrupting phrase that separates the sentence's subject from the verb that refers to it. Changing "has been shown" to "have been shown" corrects the sentence's error. The corrected sentence reads, "Early education programs, like the one started in that school district last year, have been shown to improve academic success later in life."

The subject of this sentence is "the reigning monarch," which is singular, but the verb "were," which refers to "the reigning monarch," is plural. "Were" should be changed to "was" to match the singular subject.

This sentence has a plural, compound subject, but the verb "is" agrees with a singular subject. Changing "is" to "are" corrects the sentence's error. The corrected sentence reads, "Carefully crafted plots and a brilliantly developed main character are what makes the book so compelling."

The subject of this sentence is plural ("rules"), but the verb "is" agrees with a singular subject. Changing "is" to "are" corrects the sentence's error. The corrected sentence reads, "The rules posted in the lobby are intended to be guidelines only."

In this sentence, the verb “were” does not agree with the singular subject “frequency.” The corrected sentence reads, "The frequency with which her father was bringing home bushels of raw beets was concerning to Kathy."

In this sentence, the verb does not agree with the subject. The subject “rhododendrons and lilacs” is plural, but “seems” agrees with a singular noun. The corrected sentence reads, "The rhododendrons and lilacs that line the garden path seem out of place in the shadow of the concrete structure."

The subject here is the singular gerund (verbal noun) "doing"—not the plural noun "things." Thus, the main verb should be the singular—"is," not "are."

The subject of the sentence is "spread," which is being used as a singular noun; however, the sentence's verb, "are," agrees with plural nouns, not singular ones. To correct the sentence's error, "are" should be changed to "is."

The subject in this sentece is "Massage and physical therapy." Because the sentence's subject consists of multiple nouns connected by the conjunction "and," it is a compound subject; compound subjects take plural verbs, so "helps," which agrees with singular nouns, is incorrect. The corresponding verb should be "help," not "helps."

It is easy to think that the verb "are" refers to "constituents," but in this case ("The politician, along with his many constituents, are . . ."), the verb refers back to "politician," since "along with his many constituents" is a prepositional phrase. So, the plural verb "are" is incorrect since it refers to the singular "politician," and should be replaced with the singular verb "is." The corrected sentence reads, "The politician, along with his many constituents, is opposed to the new reforms being enacted by the government."