Grammar Rule in 30 Seconds
When a number and a noun describe another noun, use a hyphen and make the noun singular.
- Use a hyphen between the number and the noun: 'A ten-minute break'.
- Always keep the noun singular: 'A two-day trip' (not days).
- Do not use a hyphen if the number comes after the noun: 'The trip lasted two days'.
Overview
- a two-day trip (the trip lasts two days)
- a five-star hotel
- a ten-minute walk
- a three-year-old child
- a 50-page report
- It was a two-hour drive. (hyphen)
- The drive was two hours long. (no hyphen, noun becomes plural)
- a three-day trip (NOT three-days)
- a five-year-old (NOT five-years-old)
- a ten-minute delay (NOT ten-minutes)
Compound Adjective Formation
| Number | Hyphen | Singular Noun | Noun Modified |
|---|---|---|---|
|
Two
|
-
|
day
|
trip
|
|
Five
|
-
|
star
|
hotel
|
|
Ten
|
-
|
minute
|
break
|
|
Six
|
-
|
page
|
essay
|
|
Three
|
-
|
hour
|
movie
|
|
Twenty
|
-
|
dollar
|
bill
|
Comparison with Predicative Forms
| Adjective Form | Predicative Form |
|---|---|
|
A two-day trip
|
The trip is two days long
|
|
A five-star hotel
|
The hotel has five stars
|
|
A ten-minute break
|
The break is ten minutes
|
Meanings
This rule describes how to turn a measurement or quantity into a single descriptive adjective for a noun.
Measurement
Describing duration, length, or distance.
“A ten-mile hike”
“A three-hour movie”
Quality/Rating
Describing the level or standard of something.
“A five-star restaurant”
“A two-page essay”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
Number-Noun + Noun
|
A two-day trip
|
|
Negative
|
Not a + Number-Noun + Noun
|
Not a two-day trip
|
|
Question
|
Is it a + Number-Noun + Noun?
|
Is it a two-day trip?
|
|
Plural
|
Number-Noun + Nouns
|
Two-day trips
|
|
Predicative
|
Noun + Verb + Number + Noun
|
The trip is two days
|
|
Complex
|
Number-Noun-Noun + Noun
|
A three-year-old child
|
正式程度
A two-day excursion (Travel)
A two-day trip (Travel)
A two-day getaway (Travel)
A two-day bender (Travel)
Compound Adjective Anatomy
Number
- Five 5
Connector
- - Hyphen
Noun
- Star Singular
Adjective vs. Predicative
Should I use a hyphen?
Is it before the noun?
Common Compound Nouns
Time
- • Two-hour
- • Ten-minute
- • Five-year
Money
- • Ten-dollar
- • Hundred-euro
Size
- • Six-foot
- • Ten-mile
按水平分级的例句
It is a two-day trip.
Es un viaje de dos días.
I have a ten-minute break.
Tengo un descanso de diez minutos.
This is a five-dollar book.
Este es un libro de cinco dólares.
He is a six-year-old boy.
Él es un niño de seis años.
We stayed at a four-star hotel.
Nos alojamos en un hotel de cuatro estrellas.
She wrote a five-page report.
Ella escribió un informe de cinco páginas.
It was a three-hour meeting.
Fue una reunión de tres horas.
I need a twenty-dollar bill.
Necesito un billete de veinte dólares.
The company signed a five-year contract.
La empresa firmó un contrato de cinco años.
They went on a six-mile run.
Fueron a correr seis millas.
It is a high-quality, ten-part series.
Es una serie de diez partes de alta calidad.
He is a world-class, three-time champion.
Es un campeón tres veces mundial.
The project requires a multi-million-dollar investment.
El proyecto requiere una inversión multimillonaria.
We are looking for a full-time, twelve-month commitment.
Buscamos un compromiso de doce meses a tiempo completo.
The team implemented a new, three-step strategy.
El equipo implementó una nueva estrategia de tres pasos.
She received a prestigious, two-year fellowship.
Recibió una prestigiosa beca de dos años.
The architect proposed a bold, fifty-story skyscraper.
El arquitecto propuso un audaz rascacielos de cincuenta pisos.
They conducted a rigorous, six-month longitudinal study.
Realizaron un riguroso estudio longitudinal de seis meses.
The novel is a sprawling, eight-hundred-page epic.
La novela es una épica extensa de ochocientas páginas.
He is a well-known, four-decade veteran of the stage.
Es un veterano de cuatro décadas muy conocido en el escenario.
The policy shift reflects a long-term, twenty-year vision.
El cambio de política refleja una visión a largo plazo de veinte años.
The device features a high-precision, sub-millimeter sensor.
El dispositivo cuenta con un sensor de submilímetro de alta precisión.
The museum houses a rare, three-thousand-year-old artifact.
El museo alberga un artefacto raro de tres mil años de antigüedad.
It was a complex, multi-layered, five-act tragedy.
Fue una tragedia compleja de cinco actos y múltiples capas.
容易混淆
Learners think the number 'two' must always be followed by a plural noun.
Learners use hyphens when the adjective comes after the verb.
Learners think all adjectives need hyphens.
常见错误
A two-days trip
A two-day trip
A two day trip
A two-day trip
A trip of two-day
A two-day trip
A two-day-trip
A two-day trip
A five-stars hotel
A five-star hotel
A 5-star hotel
A five-star hotel
The hotel is a five-star
The hotel is five-star
A ten-minutes break
A ten-minute break
A high-quality-product
A high-quality product
A three-years-old boy
A three-year-old boy
A multi-millions-dollar project
A multi-million-dollar project
A six-months study
A six-month study
A well-known-person
A well-known person
句型
It was a ___ ___ trip.
I stayed at a ___ ___ hotel.
She has ___ ___ experience.
The project is a ___ ___ commitment.
Real World Usage
I need a three-night stay.
Five-year management experience.
Best ten-minute workout!
Two-course meal deal.
Running 5-min late.
Ten-point plan revealed.
The Hyphen Rule
Singular Only
Professionalism
Native Flow
Smart Tips
Use compound adjectives to save space and sound professional.
Always check for the hyphen.
Remember: Adjective = Singular.
Use these to be concise.
发音
Hyphenation
The hyphen does not change pronunciation, but it signals that the words should be spoken as a single unit.
Compound Stress
A FIVE-star HO-tel
Stress the number and the noun being modified.
记住它
记忆技巧
Hyphens are the glue, singular is the rule.
视觉联想
Imagine a giant hyphen (-) acting like a bridge connecting a number to a singular noun, holding them together so they don't fall into the plural pit.
Rhyme
When the number comes before, keep the noun singular evermore.
Story
I went to a five-star hotel for a two-day trip. I had a ten-minute break to read a five-page book. Everything was singular, and the hyphens were everywhere!
Word Web
挑战
Write 5 sentences describing your daily routine using at least one compound adjective in each.
文化笔记
Americans use these constantly in business and casual speech to be efficient.
British English follows the same rules but may use them more in formal writing.
This is the standard for global English resumes and professional communication.
Compound adjectives evolved from Germanic roots where nouns were often combined to create new meanings.
对话开场白
What is the best five-star hotel you have ever stayed in?
How long was your longest flight?
Do you prefer a two-week vacation or two one-week vacations?
What is the most expensive ten-dollar item you have bought?
日记主题
常见错误
Test Yourself
It was a ___ (three-day) trip.
Which is correct?
Find and fix the mistake:
I have a ten-minutes break.
The meeting lasted two hours.
Compound adjectives are always plural.
A: How long is the flight? B: It's a ___ flight.
five-year / contract / a / signed / they
Which is a compound adjective?
Score: /8
练习题
8 exercisesIt was a ___ (three-day) trip.
Which is correct?
Find and fix the mistake:
I have a ten-minutes break.
The meeting lasted two hours.
Compound adjectives are always plural.
A: How long is the flight? B: It's a ___ flight.
five-year / contract / a / signed / they
Which is a compound adjective?
Score: /8
常见问题 (8)
Because it is an adjective. Adjectives in English do not have plural forms.
Yes, when it is used as an adjective before a noun.
You still use the singular noun, e.g., 'a one-day trip'.
Yes, 'a ten-dollar bill' is a perfect example.
In casual texting, maybe not, but in formal writing, it is considered a mistake.
If it comes before the noun and describes it, it's likely a compound adjective.
Not really, the rule is very consistent for measurements.
No, this is specific to English grammar.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
de + [number] + [noun]
Spanish never uses hyphens for this.
de + [number] + [noun]
French does not use compound adjectives.
Compound word
German combines the words into one without hyphens.
Noun + [number] + [counter]
Japanese does not use hyphens.
Noun + [number] + [noun]
Arabic word order is different.
Number + Measure Word + Noun
Chinese does not use hyphens.
Learning Path
Prerequisites
相关视频
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