Dickens, as well as Trollope and Thackeray, were writing novels depicting English life and customs when Victoria was queen.
What is the mistake in this sentence.
Since Dickens is the singular subject, the verb should also be singular.
Dickens, as well as Trollope and Thackeray, was writing . . .
Ms. Sue is right. The words between the commas are not part of the subject.
The mistake in this sentence is the verb tense. The verb "were" should be replaced with "was" to agree with the singular subject "Dickens."
To identify this mistake, you need to analyze the subject-verb agreement in the sentence. The subject is "Dickens, as well as Trollope and Thackeray," which is a collective noun. When a collective noun is followed by "as well as" or "along with," the verb usually agrees with the noun before the "as well as" phrase. In this case, "Dickens" is the singular noun before the phrase, so the verb should be in the singular form "was" instead of the plural form "were."