In the English language, of and does are inflections of the verb I do (do) and can have two functions:
- Main verb I do (to do).
- Auxiliary verb.
The difference between using of and the use of does is that:
- does: is used with the third person singular (he, she and it);
- of: is used with other people (I, you, we andthey).
As a main verb, of and does are inflections of the verb I do and they can mean do, do, do, do, do, do or do.
Examples:
- I of my exercises in the morning. (Me I do my morning exercises.)
- you of your exercises in the morning. (You does your morning exercises/You do you do your morning exercises.)
- he does his exercises in the morning. (He does his exercises in the morning.)
- she does her exercises in the morning. (Is it over there does her exercises in the morning.)
- we of our exercises in the morning. (We We do our morning exercises.)
- you of your exercises in the morning. (You do your morning exercises/You do your morning exercises.)
- they of their exercises in the morning. (They do their exercises in the morning.)
Let's see below the rules for using both functions.
Of and does as main verb
Like main verb, of and does are inflections of the verb I do (to do).
When used after a modal verb, I do (do) is only used as of, regardless of the subject of the sentence.
Examples:
- I will do my homework with my brother's help. (I will do my homework with my brother's help.)
- She should do the tasks before her boss arrives. (She should do chores before her boss arrives.)
Note that in the examples above, the verb I do was used after the modal verbs will and should.
See too:
- Should
- Will and Going to
- Simple Future
- Modal Verbs
In this case, even the sentence whose subject is she used of, and not does.
While push-ups of I do (to do), of and does can be used in sentences affirmatives, negative and interrogatives.
Of and does in affirmative sentences - main verb
See examples of sentences in the affirmative form where of and does are inflections of the main verb I do (to do).
Examples:
- She does her exercises in the morning. (She does her exercises in the morning.)
- I do my homework with my brother's help. (I do my homework with my brother's help.)
Of and does in interrogative sentences - main verb
Check examples of sentences in interrogative form where of and does are inflections of the main verb I do (to do).
Examples:
- Does she do her exercises in the morning? (Does she do her exercises in the morning?)
- Do you do your homework with your brother's help? (Do you do your homework with your brother's help?)
Of and does in negative sentences - main verb
See examples of sentences in the negative form where of and does are inflections of the main verb I do (to do).
Examples:
- she doesnt of her exercises in the morning. (She doesn't do her exercises in the morning.)
- I do not of my homework with my brother's help. (I don't do my homework with my brother's help.)
In the examples of negative and interrogative sentences, note that only the forms highlighted in bold are main verbs.
The other occurrences of of and does are auxiliary verbs.
IMPORTANT
In interrogative sentences and in negative sentences, only of (and not does) can be used as the main verb.
The construction of the sentence is done with the main verb in the infinitive (I do) without I'm. Soon, of it is used.
Of and does as auxiliary verb
As an auxiliary verb, of and does are used when we want to ask a question or when we want to construct a sentence in the negative form of Simple Present (Simple present).
When they play the role of helper, does and of they do not have a specific meaning.
The meaning of each of them will be determined by the main verb that accompanies them.
as with I do as the main verb, the auxiliaries of and does they can also be used in affirmative, negative and interrogative sentences.
Of and does in affirmative sentences - auxiliary verb
the auxiliaries of and does are only used in affirmative sentences to form short answers.
Examples:
- “Do you like rock music?” “Yes, I do.” (“Do you like rock?” “Yes, I do.”)
- “Does she have a sister?” “Yes, she does.” (“Does she have a sister?” “Yes, she does.”)
Of and does in negative sentences - auxiliary verb
See examples of sentences in the negative form where of and does are auxiliary verbs.
Examples:
- he does not like chocolate. (He doesn't like chocolate.)
- I do not understand Chinese. (I don't understand Chinese.)
IMPORTANT
When of and does are used as an auxiliary verb, the main verb is used in the infinitive without the I'm.
Note that the infinitive of the main verbs in the examples above are I like and I understand, respectively.
In both sentences, the I'm was not used, that is, the infinitive was used without the I'm.
The shapes do not and does not used in negative sentences can also be written in contracted form:
- do not = don’t
- does not = doesn’t
Examples:
- He doesn’t like chocolate. (He doesn't like chocolate.)
- I don’t understand Chinese. (I don't understand Chinese.)
We also use of and does in short answers negative:
Examples:
- “Do you like rock music?” “No, I do not.” (“Do you like rock?” “No, I don't.”)
- “Does she have a sister?” “No, she does not.”(“Does she have a sister? ”“No, she doesn't.”)
Of and does in interrogative sentences - auxiliary verb
Check examples of sentences in interrogative form where do and do are auxiliary verbs.
- Does she study English on Saturdays? (Does she study English on Saturdays?)
- Do they travel every year? (Do they travel every year?)
IMPORTANT
In interrogative form, of and does are used as an auxiliary verb and the main verb is used in the infinitive without the I'm.
Note that the infinitive of the main verbs in the examples above are to study and to travel, respectively.
In both sentences, the I'm was not used, that is, the infinitive was used without the I'm.
Video
Watch the video below to learn more about using of and does.
Exercises
Do the exercises below and test your knowledge of using of and does:
I. (UFPB) ____________ Beatty usually ____________ what she wants?
a) Do/get
b) Does/gets
c) Does/get
d) was/got
e) is/got
Correct alternative: c) Does/get
II. We _____________ go to the church on Wednesdays.
a) aren't
b) weren’t
c) wasn’t
d) doesn't
e) don't
Correct alternative: e) don’t
III. "______ are they ______ the dishes to help their parents?"
“Yes, they _______.”
a) Does - wash - do
b) Do - washes - do
c) Does - washes - do
d) Do - wash - do
e) Does - wash - does
Correct alternative: d) Do - wash - do
IV. He thinks he will ________ whatever he wants.
a) of the
b) does
c) do not
d) doesn't
e) don't
Correct alternative: a) of the
V. The kids _________ their homework as soon as they get home.
a) does
b) of the
c) don't
d) doesn't
e) do not
Correct alternative: b) do
Complement your studies with the texts below.
- Reported speech
- Reported speech exercises
- Simple Past
- Simple Past Exercises
- The 10 most used conjunctions in English
