In my classroom, students often ask me: “Teacher, which preposition should I use?” Prepositional phrases are one of the trickiest parts of English grammar because they’re not always logical — you can’t “reason out” why we say “at midnight” instead of “on midnight,” or “for a while” instead of “during a while.” These phrases are idiomatic by nature: you have to know them through exposure and practice. This guide focuses on three of the most common and confusing prepositions: AT, BY, and FOR.
I’ve organised over 60 prepositional phrases into three sections, grouped by the preposition and the context where each appears. Each phrase includes a clear definition and real example sentences so you can see exactly how native speakers use them in everyday conversation and writing.
Key Takeaways
- FOR expresses purpose, duration, and reason — “for breakfast,” “for ages,” “for fun,” “for a change.”
- AT marks specific times, positions, and states — “at midnight,” “at first,” “at hand,” “at work,” “at the moment.”
- BY indicates agency, means, and method — “by bus,” “by hand,” “by accident,” “by design,” “by now.”
- Context matters — the same noun pairs with different prepositions in different meanings (“for dinner” is what you eat; “at dinner” is where you are).
- These are fixed phrases — you can’t substitute prepositions freely; knowing the correct pairing comes from exposure, not rules.
Prepositional Phrases with FOR
FOR expresses purpose, duration, reason, or direction. It answers the questions “Why?” “How long?” and “What for?”
Time & Duration Phrases
For ages — a very long time (informal)
Example: I haven’t seen you for ages! Where have you been hiding?
For a while — for some period of time (indefinite)
Example: I haven’t spoken to him for a while, so I’m not sure what he’s doing now.
For ever (or forever) — permanently; always
Example: Nobody can live for ever, but we can certainly try to live well.
For the moment — for now; temporarily
Example: I’m happy living in London for the moment, but I might move next year.
For the time being — temporarily; until further notice
Example: I’m happy in my current job for the time being.
For a moment — briefly
Example: For a moment, I thought she was being serious, but then she smiled.
Purpose & Reason Phrases
For breakfast / lunch / dinner — the meal you plan to eat
Example: What did you have for breakfast today? I had scrambled eggs and toast.
For fun — for enjoyment; not seriously
Example: I don’t take sport seriously — I do it just for fun.
For love — because you care about something deeply
Example: I definitely don’t do this job for the money; I do it for love.
For luck — hoping something will bring good fortune
Example: I always wear this bracelet for luck before exams.
Contrast: Notice the difference between “for dinner” (the meal itself) and “at dinner” (the location or event). “I ate fish for dinner” (what you ate) versus “I met him at dinner” (where you met him).
Certainty & Outcome Phrases
For certain — definitely; without doubt
Example: I know for certain that I won’t be here next year.
For sure — certainly; without question (informal)
Example: That movie was great, for sure!
For good — permanently; forever
Example: I’m not coming back this time — I’m leaving for good.
For example — for instance; to illustrate
Example: You could exercise in many ways — for example, walking or swimming.
For instance — for example
Example: You should study another language — for instance, Italian or Spanish.
Appreciation & Sacrifice Phrases
For granted — without appreciation; assuming something will always be there
Example: Don’t take your parents for granted — appreciate everything they do.
For somebody’s sake — for another person’s benefit or welfare
Example: Maria was upset, so I had to stay calm for her sake.
For the sake of — in order to help or benefit someone
Example: They stayed together for the sake of their children, even though they were unhappy.
For life — permanently; as a career or commitment
Example: Working for the government used to be a job for life.
Other FOR Phrases
For a change — to do something different from usual
Example: We always go to the same restaurant. Let’s go somewhere else for a change.
For fear of — because you’re afraid of something
Example: I didn’t tell him for fear of upsetting him.
For hire — available to rent or use
Example: There are cars and vans for hire at the airport.
For nothing — without result; in vain
Example: I can’t believe the shop is closed. I came all this way for nothing!
For once — finally; for the first time in a while
Example: You’re late again! For once, can you try to arrive on time?
For sale — available to be bought
Example: There’s a lovely house for sale at the end of this street.
For short — as an abbreviation or nickname
Example: My name is Jonathan, but my family calls me Jon for short.
For safekeeping — to protect something valuable
Example: At the gym, I put my valuables in a locker for safekeeping.
For the rest of — for the remainder of
Example: I could live here for the rest of my life and be perfectly happy.
For a visit / holiday — as a guest or vacation
Example: I’m in the mood for a holiday — let’s go somewhere warm!
For a walk — to exercise or relax outdoors
Example: I was stressed so I went for a long walk to calm down.
Prepositional Phrases with AT
AT marks specific points in time, precise locations, or states of being. It answers “When exactly?” and “Where precisely?”
Time Phrases (Specific Moments)
At midnight / midday — at 12:00 AM or 12:00 PM
Example: Cinderella had to be home by midnight or her carriage would turn into a pumpkin.
At night — during the hours of darkness
Example: I can’t study during the day — I prefer to study at night when it’s quiet.
At first — initially; when something begins
Example: At first, I was happy here, but now I’m not so sure.
At last — finally; after waiting a long time
Example: At last, our bus has arrived! Thank goodness!
At the moment — right now; currently
Example: I’m living in Ireland at the moment, but I’m considering moving.
At present — right now; currently (more formal than “at the moment”)
Example: At present, I’m working for a multinational company.
At the weekend — on Saturday and Sunday
Example: I love going out with friends at the weekend.
Alex: What time does the meeting start?
Jordan: At 9:00 AM sharp. Don’t be late!
Alex: I’ll be there at 8:45 just to be safe.
Jordan: Perfect. See you then!
Location Phrases
At the door — standing outside; waiting to enter
Example: There’s somebody at the door — can you go answer it?
At the table — seated and eating
Example: The whole family sat at the table for dinner together.
At the beginning / end of — at the start or finish point
Example: I’m going to Madrid at the end of the month.
At the top / bottom of — at the highest or lowest point
Example: There’s a shop at the bottom of this hill.
At hand — nearby; available
Example: I always have a pen at hand in case I need to take notes.
At work — in your workplace
Example: I’m at work right now, so I’ll call you back later.
At school — in a school building
Example: Things were very different when I was at school.
At university — as a student in higher education
Example: I studied economics at university.
State & Condition Phrases
At fault — responsible for an error or accident
Example: Who was at fault for the car accident?
At once — immediately; all at the same time
Example: Everybody started talking at once and I couldn’t hear anyone.
At times — sometimes; occasionally
Example: At times, I feel like giving up on this project.
At least — a minimum; at the lowest point
Example: It’s cold outside, but at least it’s not raining.
At all costs — no matter what; by any means necessary
Example: I need to pass this exam at all costs.
Perception & Observation Phrases
At first sight — upon first seeing something; immediately
Example: We met at university and it was love at first sight.
At a glance — looking briefly; immediately obvious
Example: I knew at a glance that something was wrong.
At a guess — as an estimate; probably
Example: At a guess, there were about 50 people at the party.
At length — in detail; for a long time
Example: My dad could talk at length about Irish history for hours.
At random — without planning; by chance
Example: Numbers are selected at random in a lottery.
Other AT Phrases
At the age of — when a person is a certain age
Example: I learned to drive at the age of 21.
At …km per hour — traveling at a certain speed
Example: He was fined 150 pounds for driving at 200 km per hour.
At the latest — no later than; at the final deadline
Example: I need this report by Friday at the latest.
At any rate — in any case; regardless
Example: At any rate, I’m confident I’ll find a job soon.
At short notice — with little warning; suddenly
Example: She cancelled the meeting at short notice, which was frustrating.
At one’s desk — seated and working
Example: My manager spoke to me at my desk this morning.
At the same time — simultaneously; however
Example: I had fun and improved my English at the same time.
Prepositional Phrases with BY
BY indicates agency, method, means, or proximity. It answers “How?” “By what means?” and “Who did it?”
Method & Means Phrases
By bus / train / plane, etc. — using that form of transport
Example: Are you going to go there by bus or by train?
By hand — manually; without a machine
Example: My grandfather built this house by hand over five years.
By land / sea / air — using that route of travel
Example: I get sick whenever I travel by sea, so I always fly.
By phone — using a telephone
Example: Get in touch with me by phone if you need any help.
By mail / post — using postal service
Example: Do you think it’s safe to send cash by mail?
By cheque — using a bank check
Example: I’ve never paid for anything by cheque in my life.
By heart — from memory; memorized
Example: In school we had to learn poems by heart.
Agency & Causation Phrases
By accident — unintentionally; by mistake (with emphasis on lack of intent)
Example: I was so sleepy that I put salt in my coffee by accident.
By mistake — unintentionally; by error
Example: I took the wrong road by mistake and now we’re lost.
By chance — unexpectedly; by luck
Example: I found some money in my jacket pocket by chance.
By design — intentionally; on purpose
Example: I became a teacher more by accident than by design.
By luck — fortunately; through good fortune
Example: They played badly but won the match by luck.
Time & Order Phrases
By now — by this time; by this point
Example: If you don’t know me by now, you’ll never know me.
By the time — when something happens; when we reach a point
Example: I’ll have gone to bed by the time you get home.
By the way — incidentally; as additional information
Example: By the way, I won’t be able to come to class next week.
Characterization & Quality Phrases
By nature — as a natural trait or tendency
Example: German people tend to be quite organised by nature.
By birth — by nationality or heritage
Example: I grew up in England but I’m Irish by birth.
By far — by a large margin; definitely
Example: That film is by far my favourite one ever made.
By no means — certainly not; definitely not
Example: It’s by no means certain that the economy will improve.
By all accounts — according to what people say; supposedly
Example: By all accounts, Seville is a beautiful city.
Other BY Phrases
By the arm / hand — holding someone’s arm or hand
Example: He took me by the hand as we walked along the beach.
By one’s side — next to someone; close by
Example: He was by her side whenever she needed him.
By appointment — only if you arrange it in advance
Example: The museum is open at weekends by appointment only.
By invitation — only if you’re invited
Example: Membership to this club is by invitation only.
By law — according to legal requirements
Example: Dog owners must have a licence for their pets by law.
By means of — using; through
Example: I was able to afford the car by means of a bank loan.
By surprise — unexpectedly; catching someone off guard
Example: The unusual question took John completely by surprise.
By word of mouth — through direct communication; through recommendation
Example: The best form of advertising is by word of mouth.
By request — when someone asks for it
Example: Guided tours of the gallery are available by request.
By rights — according to what’s fair or just
Example: By rights, it’s my turn to play, but you can go ahead.
Common Mistakes with Prepositional Phrases
✗ Incorrect: “I’ll see you on midnight.” (wrong preposition)
✓ Correct: “I’ll see you at midnight.”
Why: Use AT for specific times, not ON. AT midnight, AT 9:00 AM, AT the weekend.
✗ Incorrect: “I went to school by foot.” (missing the article in common phrase)
✓ Correct: “I went to school on foot.” OR “I went to school by walking.”
Why: The correct phrase is “on foot,” not “by foot.” However, “by” works with other transport: “by bus,” “by train,” “by car.”
✗ Incorrect: “I haven’t seen you for a long.” (incomplete phrase)
✓ Correct: “I haven’t seen you for a long time.” OR “I haven’t seen you for ages.”
Why: FOR requires a complete noun phrase. “For a long” is incomplete; add “time” or use “for ages” instead.
Practice Quiz: Prepositional Phrases
- I haven’t seen you __________ ages! Where have you been? (for / at / by)
- I’ll be there __________ 8:00 AM sharp. Don’t be late! (for / at / by)
- She cancelled the meeting __________ short notice, which was disappointing. (for / at / by)
- I learned to drive __________ the age of 21. (for / at / by)
- Are you going to go there __________ bus or __________ train? (for / at / by)
Answers: 1. for · 2. at · 3. at · 4. at · 5. by, by
Related Articles
- ↑ Master Pillar: English Speaking
- English Collocations: Common Word Combinations
- 20 Common Idioms about Fruits in English
- ↑ Back to pillar: English Idioms (Pillar)
Frequently Asked Questions
What’s the difference between “at” and “in” for locations?
Can I use “by” and “with” interchangeably?
Why do we say “for breakfast” and not “in breakfast”?
Is “at the moment” the same as “for the moment”?
When should I use “by the way” versus “at any rate”?
Quick Test: Check Your Understanding
5 questions to test what you've learned. No sign-up required.
Comments are closed.