50+ Expressions using AT, ON, and IN (Prepositions of Time)

Mastering English prepositions can be challenging. Yet these little words pop up everywhere when we speak and write, so we have to learn how to use them!

Three of the most common prepositions of time – at, on, and in – follow certain basic rules. You can remember them more easily with the help of this AT, ON, IN triangle.

• Like the top of a triangle, AT refers to a very narrow, specific time, such as 4:30 or 7:00 o’clock.
• Like the middle of a triangle, ON refers to a slightly broader time, of one day or one date, such as Sunday or May 22.
• Like the base of a triangle, IN refers to the widest time period, such as a month, a year, a season, a decade, and so on.

A summary of these rules, along with several commonly used exceptions and expressions, is given in the table below. Watch Rebecca’s EngVid lesson video, “Master AT, ON, IN with the TRIANGLE method” to get a full explanation of the triangle and to learn how to use these prepositions. Keep practicing until the right words come to you easily and quickly.

AT
specific time	at 5:00	See you at 5:00!
	at 12:30	The meeting starts at 12:30.
	at noon	We serve lunch at noon.
	at midnight	I’ll be asleep at midnight!
(expressions)	at the moment	She’s busy at the moment.
	at the same time	Both flights arrived at the same time.
	at this time	We have no positions available at this time.
	at that time	At that time, they were in Rome.
	at some point	At some point, he’ll complete his PhD.
	at any time	Don’t call my cell at any time.
	at sunrise	The air is so clean at sunrise.
	at sunset	I love walking by the beach at sunset.
	at lunchtime	The café was crowded at lunchtime.
	at dinnertime	We’ll talk about it at dinnertime.
	at suppertime	The kids will be back home at suppertime.
	at night	By the way, Jack called at night.

ON
one day	on Monday	The concert is on Friday.
one date	on Jan 5th	I’m seeing my dentist on May 10th.
repetitive days	Tuesdays	My yoga class is on Tuesdays.
	on Independence Day	I love watching the fireworks on Independence Day!
	on your birthday	What did you do on your birthday?
	on their anniversary	He gave her a gold necklace on their anniversary.
one day + time of day	on Monday morning	Do we have a class on Monday morning?
	on Tuesday afternoon	We last spoke on Tuesday afternoon.
	on Friday evening	On Friday evening, we usually go out for dinner.
	on Thursday night	Where did you go on Thursday night?
(expressions)	on time	We made it to the exam on time.
	on the dot	The organizers started the conference on the dot.
	on the hour	The clock chimes on the hour.

IN
months	in July	They’re getting married in July.
seasons	in summer in the summer	The kids love playing outside in summer. We go camping in the summer.
years	in 2005	They moved to London in 2005.
centuries	in the 1700s	Alaska was discovered in the 1700s.
long periods	in the Middle Ages	The printing press was invented in the Middle Ages.
(expressions)	in the past	In the past, I used to drive to work.
	in the future	In the future, I’ll buy a house.
	in a few days	She’ll be back in a few days.
	in five minutes	He’s going to call back in five minutes.
	in the morning	I woke up early in the morning.
	in the afternoon	Does she sleep in the afternoon?
	in the evening	I’m going to the library in the evening.

NO PREPOSITION
	last	Last Friday, we were in London.
	next	I have a doctor’s appointment next week.
	this	He’s coming over this Thursday.
	every	We watch TV every night.
	today	Today is a brand new day.
	tomorrow	Sorry, I can’t meet you tomorrow.
	the day before yesterday	She was in the hospital the day before yesterday.
	the day after tomorrow	We’re flying to Mexico the day after tomorrow.
	soon	See you soon!
	later	Call me later!
	recently	Recently, my eyes have been bothering me.
	nowadays	Nowadays, he’s kind of depressed.
	as we speak	They’re getting married, as we speak!
	long ago	I knew someone like that long ago.
	a week ago	We signed the deal a week ago.
	a year from now	I’m not sure where I’ll be a year from now.