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When a subject (the head noun) is followed by a prepositional phrase, the verb must agree with that head noun-not with any noun inside the phrase. Writers often match the verb to a nearer noun (attraction), which produces errors like "The book on the table are mine."

Below: a short rule, a three-step check, many ready-to-copy wrong/right pairs, and quick rewrites you can paste into emails, essays, or posts.

Quick answer

Match the verb to the main subject (the head noun). Use "is" for a singular subject and "are" for a plural subject. Example: "The book on the table is mine."

Find the subject: Who or what does the sentence name?
Ignore prepositional phrases (on the table, of reports, with attachments).
Choose a singular verb (is/was) for a singular subject and a plural verb (are/were) for a plural subject.

Core rule and quick method

A prepositional phrase modifies a noun but does not change its number. The verb agrees with the head noun (the subject), not with nouns inside modifiers.

Method: 1) Identify the subject. 2) Mentally remove any prepositional phrases or modifiers. 3) Pick a verb to match the subject's number.

Wrong: The book on the table are mine. →
Right: The book on the table is mine.
Wrong: The pile of reports are overdue. →
Right: The pile of reports is overdue.

Common traps (why you get it wrong)

Attraction, long distance between subject and verb, and misleading intervening phrases cause most errors.

Attraction: the verb is pulled toward a nearer plural noun (e.g., reports).
Distance: long modifiers separate subject and verb so agreement feels unclear.
Misleading phrases: expressions like "including," "along with," and "a number of" follow special patterns.

Wrong: The files with the new data were corrupted. →
Right: The file with the new data was corrupted.
Wrong: The manager, along with his assistants, are attending. →
Right: The manager, along with his assistants, is attending.

Work examples (copyable lines for emails and reports)

Common workplace mistakes and professional corrections.

Wrong: The stack of invoices are due Friday. →
Right: The stack of invoices is due Friday.
Wrong: The report on the market trends were updated this morning. →
Right: The report on the market trends was updated this morning.
Wrong: The team with the best metrics are leading the project. →
Right: The team with the best metrics is leading the project.
Wrong: The set of reports that I emailed are on the server. →
Right: The set of reports that I emailed is on the server.

School examples (essays, lab reports, assignments)

For essays and lab write-ups, keep the subject and verb aligned to avoid lost points.

Wrong: The box of samples were contaminated. →
Right: The box of samples was contaminated.
Wrong: The history book on the syllabus are required reading. →
Right: The history book on the syllabus is required reading.
Wrong: The list of references are at the end of the paper. →
Right: The list of references is at the end of the paper.
Wrong: A number of students is missing the assignment. →
Right: A number of students are missing the assignment.

Try your own sentence

Test the whole sentence instead of the phrase alone; context often makes the correct choice clear.

Casual examples (texts, social posts, spoken language)

Correct agreement keeps meaning clear, even in short messages or chats.

Wrong: The book on the shelf are mine. →
Right: The book on the shelf is mine.
Wrong: The group of friends were waiting outside. →
Right: The group of friends was waiting outside.
Wrong: The pair of shoes are new. →
Right: The pair of shoes is new.
Wrong: The cookies on the plate was gone. →
Right: The cookies on the plate were gone.

Rewrite help - fast rewrites you can paste in

If agreement feels awkward, move the subject next to the verb or recast the sentence for clarity.

Original: The book on the table are mine. → Minimal fix: The book on the table is mine. → Cleaner: The book that's on the table is mine.
Original: The files with the new data were corrupted. → Minimal fix: The file with the new data was corrupted. → Cleaner: The new-data file was corrupted.
Original: The list of attendees are posted online. → Minimal fix: The list of attendees is posted online. → Cleaner: You can find the attendee list online.
Original: The committee of three are undecided. → Minimal fix: The committee of three is undecided. → Cleaner: The three-person committee hasn't decided.

Memory tricks, hyphenation and spacing notes

Simple mnemonics and formatting checks can speed up spotting agreement errors.

Mnemonic: "Subject first, phrase last" - pick the subject before anything that follows it.
Hyphenation: Hyphenated modifiers (long-term) do not change subject number: "The long-term goal is clear."
Spacing and punctuation: Commas and parentheticals don't alter the subject. "The book, along with the notes, is missing."
Tip: Read only the subject + verb aloud to hear whether it should be singular or plural.

Usage: The long-term plan is ready. (subject = plan → singular verb)
Wrong: There is many reasons to go. →
Right: There are many reasons to go.

Similar mistakes and when to be extra careful

These patterns look related but follow their own rules; spot them and apply the correct fix.

"There is/are": Decide if the delayed subject is singular or plural. ("There are two options." vs "There is one reason.")
"A number of" vs "the number of": "A number of students are..." (plural); "The number of students is..." (singular).
Collective nouns: American English usually treats groups as singular ("The team is..."); British English may use plural when members act individually ("The team are...").
Joined subjects: subjects joined by and = plural verb; joined by or/nor = verb agrees with the nearer subject.

Wrong: A number of students is missing the assignment. →
Right: A number of students are missing the assignment.
Wrong: The number of errors are surprising. →
Right: The number of errors is surprising.
Wrong: Either the manager or the assistants is available. →
Right: Either the manager or the assistants are available.

FAQ

Which is correct: "The book on the table is mine" or "are mine"?

"The book on the table is mine" is correct. "Book" is the subject (singular), so use "is."

How do I check subject-verb agreement when sentences are long?

Strip modifiers and prepositional phrases and read only the subject plus verb. That exposes the correct agreement instantly.

Is "the team are" ever correct?

In American English, "the team is" is standard when the group acts as one unit. British English may use "the team are" when focusing on individual members. Match your audience and stay consistent.

What's the difference between "a number of" and "the number of"?

"A number of" + plural noun takes a plural verb (A number of students are absent). "The number of" + plural noun takes a singular verb (The number of students is high).

Can automatic grammar checkers catch these errors?

Many checkers catch common attraction errors, but complex sentences and style-based choices (collectives) still need a manual check. Use the three-step method as a quick double-check.

Quick practice

Paste a sentence you're unsure about into the checker or use the three-step method: find the subject, remove modifiers, match the verb.

Keep a short list of corrected examples from this page to reference while you edit; repeated exposure makes agreement second nature.