Three questions, always in this order
A four-choice item like scientist / scientist's / scientists / scientists' is not a memory test. It is three yes-or-no questions asked in a fixed order.
Question 1. Does anything belong to this noun? Look at the word immediately after the blank. If it is a noun that the blank owns, you need an apostrophe; if it is a verb, or nothing at all, you do not.
Question 2. One owner or more than one? The sentence tells you, usually with each, both, the two, several, or a plural verb elsewhere.
Question 3. Write the owner first, then add the apostrophe. Singular owner: write the singular, add 's. Plural owner ending in s: write the plural, add the apostrophe only.
Quy tắc sống còn: viết xong danh từ chủ sở hữu rồi mới đặt dấu lược. Người Việt hay đếm theo kiểu “có s thì phẩy đứng sau s”, nên gặp children là tắc. Cứ hỏi “ai/cái gì sở hữu?” — viết đúng dạng của nó — rồi mới thêm 's hoặc dấu lược. Cách này đúng cho cả danh từ bất quy tắc.
Because the survey covered every island in the chain, it recorded each distinct pottery style.
- islands
- island's
- islands'
- islands's
Each forces a singular owner, and the noun after the blank, style, belongs to that island. So the owner is island and the form is island's. (A) has no apostrophe and so owns nothing; (C) is plural, which each forbids; (D) is not an English form. Answer (B).
Singular, plural, plural possessive
| ll@ witness | one, owning nothing |
|---|---|
| witness's | one, owning something |
| witnesses | more than one, owning nothing |
| witnesses' | more than one, owning something |
The three accounts of the eruption disagree about the hour of the first ash fall.
- witness's
- witnesses
- witnesses'
- witnesses's
Accounts belongs to the witnesses, so an apostrophe is needed and (B) is out. Three makes the owner plural, so (A), a singular possessive, is out. The plural of witness is witnesses, and a plural already ending in s takes the apostrophe alone. Answer (C).
Bẫy cốt lõi của cả nhóm câu: chữ s sau dấu lược không nói gì về số lượng của vật bị sở hữu. The team's conclusions là một đội có nhiều kết luận; the teams' conclusion là nhiều đội chung một kết luận. Nhìn danh từ đứng sau để đoán số lượng chủ sở hữu là sai hướng — manh mối luôn nằm ở phía trước.
The pronouns that never take an apostrophe
Possessive — no apostrophe ever: its, whose, theirs, ours, yours, hers, his.
Contraction — apostrophe stands for missing letters: it's = it is / it has; who's = who is / who has; they're = they are; there's = there is.
The nebula is expanding so rapidly that outer shell has already begun to dissipate.
- it's
- its
- its'
- it is
Expand the contraction and read: it is outer shell has already begun is nonsense, which disposes of (A) and (D) together. Its' does not exist in English. The slot needs the possessive determiner. Answer (B).
The chemist notebooks recorded the anomaly three years earlier was not listed as an author on the paper.
- who's
- whose
- whom's
- who
Notebooks belongs to the chemist, so the slot needs the possessive relative. Who's expands to who is, which cannot stand in front of the noun notebooks; whom's is not a form; who would need to be the subject of the clause, but notebooks already is. Answer (B).
The decision to withhold the raw data was alone, and the committee was censured for it a year later.
- their's
- theirs
- theirs'
- their
A possessive pronoun standing on its own, with no noun after it, is theirs — one word, no apostrophe anywhere. Their is a determiner and needs a noun to attach to. Answer (B).
Cách thử một giây cho its / it's và whose / who's: đọc bung dấu lược ra thành it is hoặc who is. Nghe vô nghĩa thì dấu lược sai. Phép thử này không bao giờ hỏng, và nó nhanh hơn mọi cách nhớ luật.
Irregular plurals and names ending in -s
An irregular plural does not end in s, so it takes the full 's: children's, women's, men's, people's, mice's, criteria's. The forms childrens' and womens' have no legitimate use at all — there is no word childrens for the apostrophe to follow.
For a singular name that already ends in s, standard American usage adds 's: Dickens's novels, the class's average. For a plural ending in s, the apostrophe alone: the Dickenses' house.
The 1911 hearings turned on testimony about the working conditions on the factory's upper floors.
- womens
- women's
- womens'
- womens's
Write the owner first: the plural is women, which does not end in s, so it takes the full 's. The other three all assume a nonexistent plural womens. Answer (B).
Joint ownership and separate ownership
When two names share one thing, only the second name takes the apostrophe. When each name owns its own copy, both take it — and the noun that follows is normally plural.
Darwin and Wallace's 1858 paper — one paper, written jointly.
Darwin's and Wallace's notebooks — two separate sets of notebooks.
joint paper of 1858 announced natural selection to the Linnean Society.
- Darwin and Wallace's
- Darwin's and Wallace's
- Darwin and Wallaces'
- Darwins and Wallaces
Joint and the singular paper both say the two men shared one document, so only the second name takes the apostrophe. (B) would give each man his own paper, contradicting joint; (C) invents a plural Wallaces; (D) has no possessive at all. Answer (A).
Apostrophes that must not be there
An apostrophe never makes a plural. Not for ordinary nouns (photographs, not photograph's), not for decades (the 1950s), not for initialisms (CDs, MRIs).
The archive catalogues more than two thousand produced between 1890 and 1914.
- photograph's
- photographs
- photographs'
- photographs's
Nothing after the blank belongs to the photographs — produced… is a participle modifying them. With no ownership, there is no apostrophe, and two thousand makes the noun plural. Answer (B).
Ngược lại cũng là bẫy: có những câu chỗ trống nằm ngay trước một động từ, và học sinh vẫn gắn dấu lược vì thấy chữ s. The lichen colonies grow slowly — grow là động từ, không có gì bị sở hữu, nên không có dấu lược. Cứ nhìn từ ngay sau chỗ trống trước khi làm gì khác.
Ba dạng nhiễu được dùng đi dùng lại ở nhóm câu này: (1) thêm dấu lược cho danh từ số nhiều bình thường; (2) đặt dấu lược trước s khi chủ sở hữu là số nhiều; (3) viết its' hoặc who's thay cho its và whose. Nhận mặt được ba dạng đó là loại được ba phương án trước khi kịp phân vân.