This (These) two are happy

Using the correct demonstrative-this, that, these, those-fixes a small but common error. The familiar slip "This books are" happens when a singular demonstrative (this) is paired with a plural head noun (books).

Below: a quick rule and test, many before/after examples (work, school, casual), short rewrites that improve clarity, a compact checklist you can use while editing, and a simple memory trick with hyphenation and spacing notes.

Quick answer

Use these or those with plural nouns (These books are...). Use this or that with singular nouns (This book is...).

Plural head noun → these/those. Example: books → these books.
Singular head noun → this/that. Example: box of books → this box.
Quick test: if they/they are fits, use these; if it/it is fits, use this.

Core grammar: the fast rule and replacement test

This/that are singular demonstratives; these/those are plural. Match the demonstrative to the grammatical head (the real subject), not to a nearby word.

Replacement test: swap the phrase for a pronoun. If "they are" works, use these. If "it is" fits, use this.

Head noun matters: "this set of books is" (set = singular) vs "these books are" (books = plural).
Numbers force plural: "these two options" (not "this two").
Collectives and measured phrases can be singular: "this team is", "this 100-page report is".

Wrong: This books are dusty.
Right: These books are dusty.
Wrong: This two are missing.
Right: These two are missing.

Examples you can copy: common wrong/right pairs

Short drills: read the wrong sentence, identify the head noun, then read the corrected form. These examples reflect common email, note, and post mistakes.

Wrong: This apples on the counter are bruised. -
Right: These apples on the counter are bruised.
Wrong: This people in the queue looked tired. -
Right: These people in the queue looked tired.
Wrong: This results show an upward trend. -
Right: These results show an upward trend.
Wrong: This notes from class were useful. -
Right: These notes from class were useful.
Wrong: This chairs are in the conference room. -
Right: These chairs are in the conference room.
Wrong: This files were uploaded to the wrong folder. -
Right: These files were uploaded to the wrong folder.
Wrong: This pictures from the event are on my phone. -
Right: These pictures from the event are on my phone.

Work examples: emails, reports, and tickets (3 cases)

At work, demonstrative errors make messages look careless. Match the demonstrative to the head noun to keep updates precise.

Wrong: This invoices for April need approval. -
Right: These invoices for April need approval.
Wrong: This screenshots demonstrate the user flow. -
Right: These screenshots demonstrate the user flow.
Wrong: This deliverables include the design files. -
Right: These deliverables include the design files.

School examples: essays, lab reports, and notes (3 cases)

Students often write quickly and mismatch demonstratives. Fixing that one word improves clarity and reduces marks-off.

Wrong: This results of the survey support the hypothesis. -
Right: These results of the survey support the hypothesis.
Wrong: This chapters cover Victorian poetry. -
Right: These chapters cover Victorian poetry.
Wrong: This students were assigned to Group B. -
Right: These students were assigned to Group B.

Casual examples: texting, social posts, and chat (3 cases)

Listeners may forgive small slips in casual chat, but correct agreement reads cleaner in public posts or messages to people you don't know well.

Wrong: This photos from last night are hilarious. -
Right: These photos from last night are hilarious.
Wrong: This friends are coming over. -
Right: These friends are coming over.
Wrong: This snacks were eaten already. -
Right: These snacks were eaten already.

Try your own sentence

Test the whole sentence rather than the phrase alone: context usually reveals the head noun and the correct demonstrative.

Rewrite help: fix + improve (5 rewrites)

A direct swap often works. Sometimes a short rewrite improves rhythm or emphasis. Each example below fixes the demonstrative and tightens the sentence.

Rewrite:
Wrong: This books are available in storage. -
Rewrite: These books are available in storage.
Rewrite:
Wrong: This candidates are qualified. -
Rewrite: These candidates are qualified; I recommend interviewing them.
Rewrite:
Wrong: This files that we archived contain private info. -
Rewrite: These archived files contain private information.
Rewrite:
Wrong: This charts show sales growth. -
Rewrite: The charts show sales growth. (Or: These charts show sales growth.)
Rewrite:
Wrong: This books on the syllabus are required. -
Rewrite: The books on the syllabus are required. (Clearer than "These books...")

Fix your own sentence: a compact checklist

Use this three-step check when you spot a demonstrative or a sentence that reads off.

1) Identify the head noun: is it singular or plural? (box vs books)
2) Replacement test: try they/they are → these; it/it is → this.
3) If it still sounds odd, rewrite: change the subject or use a singular head (this set of..., this box of...).

Usage: "This box of books is missing." Head = box (singular) → this is correct.
Usage: "These books are missing." Replacement: "They are missing" → these is correct.

Real usage and similar pitfalls

Watch collective nouns, measured quantities, and style choices (for example, data). Also check subject-verb number whenever you correct the demonstrative.

Collectives: "this team is" (team = singular head) vs "these players are" (players = plural head).
Data: some guides treat data as plural ("these data are"), others as a mass noun ("this data is"). Follow the guide you use.
Also fix verb agreement: "these data shows" → "these data show" (or "this data shows" if your style treats data as singular).

Usage: This batch of orders is delayed. (batch = singular head) - correct.
Usage: These players are ready. (players = plural head) - correct.
Usage: Wrong: Those is the reason we paused. -
Right: That is the reason we paused.

Memory trick plus hyphenation & spacing notes

Memory trick: "This = Singular, These = More than One." Or: if you can say they, use these; if you can say it, use this.

Formatting note: demonstratives don't use hyphens. Keep normal spacing and punctuation; this fix is grammatical, not typographic.

Mnemonic: This → 1 (single), These → 2+ (plural).
No hyphenation: write "these books", not "these-books".
Spacing: no extra space between demonstrative and noun; punctuation follows normal rules.

Usage: Correct: These books are on the table.
Usage: Correct: This box of records is archived.

FAQ

Can I say 'this books' in casual speech?

You might hear it in quick speech, but it's nonstandard. In writing and formal speech, use these with plural nouns to avoid distracting readers.

When is 'this' correct before a phrase that mentions many items?

When the grammatical head is singular: "this box of books is missing" (box = singular). Always identify the head noun.

How do I quickly test whether to use 'these'?

Replace the noun phrase with a pronoun: if "they are" fits, use these; if "it is" fits, use this.

Is 'these data are' always required?

Style guides differ. Many academic guides use "these data are"; others treat data as a mass noun ("this data is"). Use the guide for your context.

What habit stops me from repeating this mistake?

Use the three-step checklist during revisions (identify head noun → replacement test → rewrite if needed). Repeat the test aloud: it becomes automatic with practice.

Still unsure about a sentence?

Paste the sentence into a grammar checker or try the replacement test: make the swap, read the sentence aloud, and apply the checklist until the pattern feels natural.