'this' vs. 'these'

Mixing a singular demonstrative with a plural noun causes errors like "This books are" instead of "These books are." Demonstratives must match the noun's number: use this/that for one, these/those for more than one.

Below: a short rule, practical checks, many realistic examples for work, school, and casual contexts, quick rewrite templates you can paste, and memory tricks to spot the error fast.

Quick answer

Use this for one item and these for more than one. Say "These books are..." not "This books are."

This = singular (this book).
These = plural (these books).
Check the head noun's number-if it's plural, use these or those.

Core grammar: demonstratives must match number

Demonstratives (this, that, these, those) agree with the number of the noun they point to. Use this/that for singular nouns and these/those for plural nouns. Number agreement is not optional.

Example error: "This books are new." The head noun is books (plural), so the correct demonstrative is these: "These books are new."

this + singular noun: this book, this pen
these + plural noun: these books, these pens
If the verb is plural (are/were), the demonstrative should normally be plural too (these/those).

Spotting the noun to check

Find the head noun the demonstrative refers to. Even if adjectives or prepositional phrases separate them, base your choice on the head noun.

"this stack of books" → stack is singular → this is correct.
"these collections of poems" → collections is plural → these is correct.
When unsure, rephrase so the demonstrative sits next to the noun: "These books arrived."

Examples (work, school, casual) - wrong/right pairs

Read each wrong sentence, note the noun's number, and compare it to the corrected version. Use these as templates for your own sentences.

Work - Wrong: This books are waiting in the break room.Work -
Right: These books are waiting in the break room.
Work - Wrong: This books contain last quarter's client files.Work -
Right: These books contain last quarter's client files.
Work - Wrong: This manual and these guides is on the shelf.Work -
Right: This manual and these guides are on the shelf.
School - Wrong: This books are required reading for the course.School -
Right: These books are required reading for the course.
School - Wrong: This books in the syllabus were optional.School -
Right: These books in the syllabus were optional.
School - Wrong: This textbook and those handouts was assigned last week.School -
Right: This textbook and those handouts were assigned last week.
Casual - Wrong: This books I picked up at the sale are hilarious.Casual -
Right: These books I picked up at the sale are hilarious.
Casual - Wrong: This books on the porch look like they belong to the neighbor.Casual -
Right: These books on the porch look like they belong to the neighbor.
Casual - Wrong: This ones are my favorites.Casual -
Right: These ones are my favorites.

Rewrite help: quick fixes you can paste

If you spot "This books are" in your writing, use one of these fast fixes depending on the structure.

Plural noun: change this → these. Example: "These books are on my desk."
Singular head noun with plural phrase: keep this and treat the head noun as singular. Example: "This stack of books is heavy."
Move the noun next to the demonstrative: "These books (that I ordered) arrived."

Rewrite:
Wrong: This books are on my desk. |
Correct: These books are on my desk.
Rewrite:
Wrong: This books that you mentioned were helpful. |
Correct: Those books that you mentioned were helpful.
Rewrite:
Wrong: This books of poetry impressed me. |
Correct: These books of poetry impressed me. Or: This collection of poems impressed me.

Try your own sentence

Test the whole sentence, not just the phrase. Context clarifies the intended head noun and the right demonstrative.

Memory tricks and quick checks

Two quick checks catch most errors: count the noun (one or more) and listen to the verb. If it should be are/they, use these/them; if it should be is/it, use this/that.

Swap test: replace the demonstrative with the noun phrase next to it. If it reads naturally, your choice is probably correct.
Verb test: plural verb → these/those; singular verb → this/that.
Simple mnemonic: This → Single. These → Several. Or: If you'd say "They are," use these.

Real usage and tone: speech, email, dialects

Casual speech sometimes tolerates mismatches and listeners understand, but written communication-emails, reports, assignments-should follow standard agreement to avoid looking careless.

Regional speech patterns may differ; for clarity in formal contexts, match demonstratives and noun number consistently.

Informal: people may say nonstandard forms, but avoid them in writing.
Formal: standard agreement is expected-this/that for singular, these/those for plural.
Emphasis note: use your demonstrative deliberately-"This collection is helpful" vs "These essays are helpful."

Spacing, punctuation and hyphenation notes

Do not hyphenate demonstratives and nouns: write "these books," not "these-books." The demonstrative is a separate word with normal spacing.

Don't add apostrophes to demonstratives. Use apostrophes only for possessives of the noun: "these books' covers" (plural possessive) or "this book's cover" (singular possessive).

No hyphen: these books, this book, these stacks of paper.
Plural possessive: These books' covers are torn. (books' = plural possessive)
Singular possessive: This book's cover is torn. (book's = singular possessive)

Similar mistakes to watch for

Other common errors come from not checking number: "These is," "This ones," or mixing that/those. Fixing demonstrative-number agreement often clears up verb and possessive mistakes nearby.

Wrong: These is my favorite. →
Right: This is my favorite. or These are my favorites.
Wrong: This ones are new. →
Right: These ones are new.
Wrong: That books are missing. →
Right: Those books are missing.

FAQ

Is "This books are" ever correct?

Not in standard English. "This" is singular and "books" is plural. In speech some dialects may allow it, but it is not correct for writing.

Should I say "these books is" or "these books are"?

Use "these books are." These is plural and pairs with the plural verb are.

What about "this collection of books are"?

If the head noun is collection (singular), use "this collection of books is." If you mean the books themselves, use "these books are."

How do I quickly fix "This books are" in an email?

Replace "this" with "these" when referring to multiple books. If you meant a singular container, rewrite: "This box of books is on my desk."

Why do native speakers sometimes use odd demonstratives in speech?

Casual speech and some dialects relax grammar; listeners typically understand. For writing and formal contexts, follow standard agreement to avoid confusion.

Want to check a sentence quickly?

Paste your sentence into a grammar checker to catch demonstrative-number mismatches like "This books are." A quick tool will suggest the correct demonstrative and verb so you can paste the fix into your message.