Articles & Prepositions (Basics)

Level B2–C2 · a/an/the & in/on/at

◎What you'll master

Use a / an for the first mention of a singular countable noun and for jobs (she is an engineer).
Choose a or an by sound, not spelling — a university, an hour.
Use the for something specific, already mentioned, or unique (the sun, the manager we met).
Use zero article for general plural and uncountable nouns (Books are…, Water is…).
Pick the right preposition of time and place: in / on / at.

1a / an — the first-mention article

Use a / an before a singular countable noun when it is new information — the listener doesn't yet know which one you mean. It also names jobs and roles.

I saw a cat in the garden. · She is an engineer. · What a day!

Choose by sound, not spelling

Use a before a consonant sound and an before a vowel sound. Listen to the first sound of the next word.

a + consonant sound	an + vowel sound
a university (/j/ — a "you" sound)	an hour (the h is silent)
a European country	an honest answer
a one-way street (/w/)	an MBA (/em/)

⚠ Watch out — it's the sound that decides: an university → a university, and a hour → an hour.

2the — the specific article

Use the when the noun is specific — you and the listener both know which one. That happens when it is:

Reason	Example
already mentioned	I bought a book. The book was cheap.
defined by the sentence	The manager we met was helpful.
unique — only one exists	the sun · the moon · the internet

Second mention: A dog followed me home. The dog was hungry.

⚠ Watch out — switch to the once the thing is known: A manager we met was helpful → The manager we met was helpful.

3Zero article — talking in general

Use no article (zero article) with plural or uncountable nouns when you mean them in general, not a specific set.

Books are expensive. · Water is essential for life. · I like music.

Most names, meals, and languages also take no article.

I had breakfast in London and we spoke English.

⚠ Watch out — don't add the to a general statement: The water is important for life → Water is important for life.

4Prepositions of time — in / on / at

Think of the size of the time period: in is the biggest, at is a single point.

Preposition	Used for	Example
in	months, years, seasons, parts of the day	in July · in 2025 · in summer · in the morning
on	days and dates	on Monday · on 3 May
at	clock times, night, the weekend	at 6 o'clock · at night · at the weekend

A quick memory hook

at a point (a time on the clock), on a day (a square on the calendar), in a longer stretch (a month, a season, a year).

5Prepositions of place — in / on / at

Same three words, a parallel logic: in = inside an area, on = touching a surface or line, at = a point.

Preposition	Used for	Example
in	enclosed spaces, areas, cities/countries	in a box · in London · in the room
on	surfaces and lines	on the table · on the wall · on the coast
at	a point or a place	at the door · at the station · at home

⚠ Watch out — a city is an area you are inside: at London → in London; but a specific point: at the station.

6Putting it together

In real sentences, articles and prepositions work side by side. Decide the article first (is the noun new, specific, or general?), then choose the preposition by the size of the time or place.

She is an engineer. On Monday, in the morning, she took a train to the station in London.

Order of decisions

First mention → a / an. Known or unique → the. General plural/uncountable → no article. Then: point of time/place → at, day/surface → on, longer stretch/enclosed area → in.

Practice — 15 questions with instant feedback

0 / 15 correct

Question 1

It usually happens ______ night.

Question 2

She is ______ artist.

Question 3

We first met (month) July.

Question 4

The shop reopens (day) Monday.

Question 5

I waited for you ______ the door.

Question 6

He hopes to win ______ university place.

Question 7

The keys are (place) the table.

Question 8

______ water is essential for all living things.

Question 9

I'll meet you (place) the station at six.

Question 10

We watched ______ sun set over the sea.

Question 11

She always feels sleepy (time) the afternoon.

Question 12

Last week I read ______ interesting book about the deep ocean.

Question 13

The company was founded (date) 3 May, over a century ago.

Question 14

In general, ______ books are more expensive than they used to be.

Question 15

______ manager we met yesterday explained the new rules to the whole team.

✎Fix the Error

Each sentence has one mistake in the underlined word. Type the correction and check.

1.He studies at an university in the north.

2.The meeting is in Monday afternoon.

3.I go for a run at the morning before work.

4.She is engineer at a tech firm.

5.The water is important for all living things.