‘An’, ‘one’, and ‘each’ are all examples of determiners as they help to specify the noun in some way. Let’s explain the differences between them when used with singular nouns:
- An: This is an indefinite article that is used before singular countable nouns that start with a vowel sound. It doesn’t specify which particular thing or person you are referring to. For example, in the sentence “I’ve got an idea”, ‘an’ is used because ‘idea’ starts with a vowel sound. It means you have a single idea, but it doesn’t specify what the idea is.
- One: This is a number that refers to a single unit or thing. It is more specific than ‘an’ because it emphasizes singularity and can be used with any singular noun, regardless of whether it starts with a vowel or consonant. In the sentence “They are here for one reason”, ‘one’ is used to emphasize that there is only a single reason for their presence.
- Each: This is used to refer to every one of two or more things or people, considered separately. It emphasizes individuality within a group. In the sentence “Each person gets a bottle of beer”, ‘each’ is used to indicate that every single person in the group will receive their own bottle of beer.
Profiling Research
In the English Grammar Profile, A2 point 28 in the category of DETERMINERS is defined as:
increasing range of quantifying determiners with singular nouns (‘each’, ‘an’, ‘one’ and numbers)
Also note that, in the English Vocabulary Profile:
one day = A2 used to talk about something that happened in the past
one day/some day/one of these days = B1 at some time in the future
For example:
One day, I was outside the room
and suddenly her playing stopped.
In the phrase “one day,” the word “one” is indeed a quantifying determiner. It specifies the quantity of the noun that follows it, which in this case is “day.” So “one” is determining that there is a single day being referred to. However, in this context, it’s used more as an idiomatic expression to mean “on a certain day” or “once upon a time,” rather than specifying a particular day.
The phrase “one day” is an adverbial phrase of time. It tells us when the action of the sentence took place. In this case, it’s not specifying a particular day, but rather it’s used to indicate that the event happened at an unspecified time in the past. The comma after “one day” is used to separate this introductory phrase from the rest of the sentence. This is a common structure in English to start a narrative or story about something that happened in the past.
One day, another pandemic will sweep the globe.
And maybe one day I will be sadder and I will be less optimistic,
but someone else will bring that hope to me.
many people share with me this wish,
that some day a more advanced version of Siri,
the digital assistant on Apple‘s iPhone,
will be more like a best friend,
someone who will listen when others won’t.
Even though he lost last night,
he‘ll win one of these days.
A search in iWeb corpus for:
each|an|one _NN1
1 ONE THING 587964
2 AN EXAMPLE 440517
3 AN OPPORTUNITY 390589
4 AN EMAIL 364587
5 AN ISSUE 358269
6 AN AREA 254162
PELIC STUDENT EXAMPLE:
Earthquakes destroy everything in an area and stir up dust from the destruction.
Female, Level 3, Writing class
7 AN OPTION 253985
8 AN IDEA 247591
9 ONE WAY 245613
I like to know what the people think,
their feelings and their frustrations,
or why they act in one way instead of another one.
Spanish, Male, Level 4, Reading class
EXPERT EXAMPLE (B2 phrase)
You won’t convince him one way or the other.
10 AN INCREASE 222948
11 AN INTERVIEW 217759
12 ONE SIDE 216577
13 AN EYE 215361
14 AN IMAGE 198147
15 AN EVENT 196983
16 AN APPLICATION 193672
17 ONE PERSON 192137
18 AN END 190066
19 AN EFFORT 181549
20 AN ARTICLE 180031
21 AN ACCOUNT 171451
22 AN ATTEMPT 170235
23 AN EMPLOYEE 167941
24 AN ORDER 167392
25 AN AVERAGE 161468
26 ONE POINT 161139
27 AN ERROR 158257
28 AN EMERGENCY 154446
29 AN INDIVIDUAL 151132
30 AN ORGANIZATION 145635
31 AN EXPERT 144135
32 AN OBJECT 140566
33 AN ARRAY 138671
34 AN ADULT 135645
35 ONE HAND 131772
36 AN ITEM 126080
37 AN IMPACT 119928
38 AN APPOINTMENT 119219
39 AN INTEREST 119058
40 ONE PLACE 117815
41 AN UNDERSTANDING 114049
42 AN APP 110073
43 AN AGREEMENT 108861
44 AN ANSWER 105781
45 EACH SIDE 105501
Therefore, there are differences in preferences,
and each side has their own reasons.
Arabic, Male, level 5, writing class
46 AN UPDATE 105045
47 AN ARTIST 104901
48 AN ACCIDENT 103605
49 AN OVERVIEW 103072
50 AN INVESTMENT 99053
51 AN ALTERNATIVE 96291
52 AN EXTENSION 95181
53 AN ACTION 93858
54 AN ACT 92554
55 AN ENVIRONMENT 92188
56 AN AIR 88911
57 AN OFFICE 88522
58 ONE REASON 86596
They are here for one reason and one reason only.
59 AN ANIMAL 85862
60 AN OFFER 84501
61 AN ART 82144
62 AN INDUSTRY 81796
63 ONE STEP 81525
64 AN ATTACK 80984
65 AN INVESTIGATION 80420
66 EACH PERSON 79964
Also, each person is to get a bottle of vodka.
67 AN INTRODUCTION 78767
68 ONE END 77489
69 ONE PIECE 76249
70 AN AUDIENCE 75683
71 AN ARGUMENT 75352
72 AN EMPLOYER 74843
73 AN ATTORNEY 73891
74 AN EXPERIENCE 73194
75 ONE MAN 71805
76 EACH STUDENT 70656
77 AN INTERNET 70253
78 AN AGENT 68112
79 AN ADVANTAGE 67937
80 AN ENEMY 64324
81 AN OFFICER 63998
82 AN EXPLANATION 63696
83 AN ELEMENT 63286
84 AN EXCEPTION 62052
85 AN EFFECT 61972
86 AN ARMY 61548
87 ONE PART 61007
88 AN EMPHASIS 60547
89 ONE EXAMPLE 60419
90 AN EXCUSE 58804
91 AN APARTMENT 58725
92 AN INDICATION 58634
93 AN INJURY 58250
94 AN ABUNDANCE 55834
95 AN AWARD 55160
96 AN APPLE 55149
97 AN IPHONE 54652
98 AN E-MAIL 54575
99 AN ASSET 54230
100 AN EXECUTIVE 52470
A2 vocabulary in the above search:
accident, air, apartment, appointment, area, art, artist, idea, mail, offer, office, order, piece, point, reason, side, way
A search in the iWeb corpus for:
one _NNT * * _V*D
1 ONE DAY WHEN I WAS 1087
My old lady took a bottle of pills one day when I was at school.
2 ONE DAY, I WAS 851
3 ONE TIME WHEN I WAS 652
4 ONE TIME, I WAS 377
5 ONE DAY WHEN HE WAS 369
6 ONE TIME, IT WAS 355
7 ONE NIGHT WHEN I WAS 351
8 ONE DAY WHILE I WAS 330
9 ONE DAY, HE WAS 286
10 ONE DAY AS I WAS 263
11 ONE DAY. I WAS 260
12 ONE DAY. IT WAS 254
13 ONE NIGHT, I WAS 238
14 ONE DAY, I DECIDED 217
15 ONE DAY, I HAD 208