DO — Auxiliary Verb (One-Page Notes)

📘 DO --- Auxiliary Verb (One-Page Notes)

For printing / copying · British English pronunciation · Core rules + common mistakes

1️⃣ Core Rule (Most Important)

Once you use do / does / did, the main verb must be in the base form!

Correct	Wrong
Does she like coffee?	Does she likes coffee?
Did you go home?	Did you went home?
They don't finish their task.	They don't finishes their task.

2️⃣ How to Use do / does / did

Auxiliary	Used with	Tense	Example
do /duː/	I, you, we, they	Present simple	Do you like English?
does /dʌz/	he, she, it, singular nouns	Present simple	Does she like coffee?
did /dɪd/	all subjects	Past simple	Did you like the class?

3️⃣ Five Main Functions

Function	Structure	Example
Questions	Do/Does/Did + subject + base verb?	Do you speak English?
Negatives	Subject + don't/doesn't/didn't + base verb	She doesn't like coffee.
Emphasis	do/does/did + base verb	I do like English.
Short answers	Yes, I do. / No, she doesn't.	Did they come? Yes, they did.
Substitution	Avoid repetition	I like coffee, and she does too.

4️⃣ DO as a Main Verb

Sentence	Part of speech	Meaning
I do my homework.	Main verb	do homework
She does the dishes.	Main verb	wash the dishes
He did the laundry.	Main verb	do the laundry

As a main verb, do can take -s / -ed / -ing.

As an auxiliary, the verb after do must be in the base form.

5️⃣ Do Not Mix!

Wrong	Correct
I do be happy.	I am happy.
Do you are tired?	Are you tired?
She doesn't can swim.	She can't swim.
Do you can help me?	Can you help me?

The verb be and modal verbs form questions and negatives by themselves. They do not use do/does/did.

6️⃣ Pronunciation Focus (British English)

Word	Strong form	Weak form
do	/duː/	/də/
does	/dʌz/	/dəz/
did	/dɪd/	/dɪd/
don't	/dəʊnt/	---
doesn't	/ˈdʌznt/	---
didn't	/ˈdɪdnt/	---

Linking:

Do you → /də juː/ or /duː juː/

Did you → /dɪdʒuː/

Does she → /dʌz ʃiː/

7️⃣ Common Mistakes

Wrong	Correct	Reason
Does she likes coffee?	Does she like coffee?	After does, use the base verb.
Did you went?	Did you go?	After did, use the base verb.
I don't am tired.	I am not tired.	Be does not use do.
She doesn't can swim.	She can't swim.	Modal verbs do not use do.
Do he like English?	Does he like English?	Third person singular uses does.
They don't finishes.	They don't finish.	After do, use the base verb.

✅ One-Sentence Summary

Do / Does / Did are auxiliary verbs used to form questions, negatives, and emphasis; they are always followed by the base form of the verb. The verb be and modal verbs do not use them.

Printable · Copyable · Best kept on your desk

Here is a complete Teacher's Script for a class on DO as an Auxiliary Verb. It is written in English and can be read aloud in class. It includes teacher talk, board work, examples, and interactive practice.

Teacher's Script: DO as an Auxiliary Verb

Time: About 8--10 minutes

Level: Beginner to Elementary

Topic: Do / Does / Did as auxiliary verbs

1. Greeting and Warm-up (1 minute)

Teacher:

Good morning, everyone. Today we are going to learn about a very small but very important verb: DO .

We will look at do , does , and did as auxiliary verbs .

Auxiliary verbs are also called "helping verbs." They help the main verb.

Let's start with a quick question.

Do you like English?

(Pause for answers.)

Good. You just heard the word do. That is our topic today.

2. What is an Auxiliary Verb? (1 minute)

Teacher:

An auxiliary verb is a helping verb. It works together with a main verb.

For example:

Do you like English?

Here, do is the auxiliary verb, and like is the main verb.

Now, look at these three sentences:

Do you like English?
Does she like coffee?
Did they finish their task?

What do you notice?

(Pause.)

Yes --- we use do , does , and did to make questions.

But they are not the same. Let's see when to use each one.

3. Do, Does, Did --- When to Use (2 minutes)

Teacher:

(Write on the board.)

DO --- with I, you, we, they --- present tense

DOES --- with he, she, it, singular nouns --- present tense

DID --- with all subjects --- past tense

Let's read the examples together.

Do you like English?

Does she like coffee?

Did you like the class?

(Point to the board.)

Remember:

Do and does are for the present.

Did is for the past.

And did is the same for everyone --- I, you, he, she, it, we, they.

4. The Golden Rule (1 minute)

Teacher:

Now, here is the most important rule. Please listen carefully.

Once you use do, does, or did, the main verb must be in the base form.
Do not add -s, -ed, or -ing.

Look at these correct and incorrect sentences.

(Write on the board.)

Correct	Incorrect
Does she like coffee?	Does she likes coffee?
Did you go home?	Did you went home?
They don't finish their task.	They don't finishes their task.

(Point to the correct ones.)

After does , we say like , not likes .

After did , we say go , not went .

After don't , we say finish , not finishes.

Everyone, repeat after me:

Does she like coffee?

(Students repeat.)

Did you go home?

(Students repeat.)

They don't finish their task.

(Students repeat.)

5. Five Functions of DO (2 minutes)

Teacher:

Now let's see what do, does, and did can do. They have five main jobs.

(Write on the board.)

1. Questions

Do you speak English?

Does she like coffee?

Did they come yesterday?

2. Negatives

I do not understand.

She does not like coffee.

They did not finish their task.

3. Emphasis

I do like English.

She does play the piano every day.

They did finish the project.

4. Short answers

Do you like coffee? --- Yes, I do. / No, I don't.

Does she like tea? --- Yes, she does. / No, she doesn't.

Did they come? --- Yes, they did. / No, they didn't.

5. Substitution

I like coffee, and she does too.

He doesn't like tea, but I do.

(Pause.)

These are the five jobs. Do you have any questions so far?

(Answer any questions briefly.)

6. DO as a Main Verb (1 minute)

Teacher:

But wait --- do can also be a main verb. That means it is not helping another verb. It is the main action.

Look at these examples:

I do my homework.

She does the dishes.

He did the laundry.

Here, do means "做" --- to perform an action.

When do is a main verb, it can take -s, -ed, or -ing.

But when it is an auxiliary verb, the next verb must be in the base form.

So, compare:

I do my homework. (main verb)
I do like English. (auxiliary verb)

In the first sentence, do is the action.

In the second sentence, do helps like .

The main verb is like.

7. Common Mistakes (1 minute)

Teacher:

Now let's look at some common mistakes. Please correct these sentences with me.

(Write on the board, one by one.)

Does she likes coffee?
(Students: Does she like coffee?)
Did you went?
(Students: Did you go?)
I don't am tired.
(Students: I am not tired.)
She doesn't can swim.
(Students: She can't swim.)
Do he like English?
(Students: Does he like English?)
They don't finishes.
(Students: They don't finish.)

Teacher:

Remember two important points:

Be verbs and modal verbs do not use do/does/did .

They make questions and negatives by themselves.

For example:

Are you tired?

Can you help me?

She is happy.

He can't swim.

8. Summary and Homework (1 minute)

Teacher:

Let's summarize.

Do , does , and did are auxiliary verbs.

They help us make questions, negatives, emphasis, short answers, and substitutions.

After do / does / did , the main verb is always in the base form .

Be verbs and modal verbs do not use them.

Your homework:

Write five sentences using do , does , or did .

Use at least one question, one negative, and one short answer.

That's all for today. Thank you, everyone.

See you next class!

End of Teacher's Script

📘 DO --- Auxiliary Verb 一页笔记版

打印/抄写用 · 英音标注 · 核心规则 + 常见错误

1️⃣ 核心规则（最重要）

用了 do / does / did，后面主要动词必须用「原形」！

正确	错误
Does she like coffee?	Does she likes coffee?
Did you go home?	Did you went home?
They don't finish their task.	They don't finishes their task.

2️⃣ do / does / did 怎么用？

助动词	用于	时态	例子
do /duː/	I, you, we, they	一般现在时	Do you like English?
does /dʌz/	he, she, it, 单数名词	一般现在时	Does she like coffee?
did /dɪd/	所有人称	一般过去时	Did you like the class?

3️⃣ 五大功能

功能	结构	例子
疑问句	Do/Does/Did + 主语 + 动词原形？	Do you speak English?
否定句	主语 + don't/doesn't/didn't + 动词原形	She doesn't like coffee.
强调	do/does/did + 动词原形	I do like English.
简略回答	Yes, I do. / No, she doesn't.	Did they come? Yes, they did.
替代动词	避免重复	I like coffee, and she does too.

4️⃣ do 也是实义动词

句子	do 词性	意思
I do my homework.	实义动词	做作业
She does the dishes.	实义动词	洗碗
He did the laundry.	实义动词	洗衣服

实义动词 do 可加 -s / -ed / -ing。

助动词 do 后面的动词必须用原形。

5️⃣ 不能混用！

错误	正确
I do be happy.	I am happy.
Do you are tired?	Are you tired?
She doesn't can swim.	She can't swim.
Do you can help me?	Can you help me?

be 动词和情态动词自己构成疑问和否定，不用 do/does/did。

6️⃣ 发音重点（英音）

单词	强读	弱读
do	/duː/	/də/
does	/dʌz/	/dəz/
did	/dɪd/	/dɪd/
don't	/dəʊnt/	---
doesn't	/ˈdʌznt/	---
didn't	/ˈdɪdnt/	---

连读：

Do you → /də juː/ 或 /duː juː/

Did you → /dɪdʒuː/

Does she → /dʌz ʃiː/

7️⃣ 常见错误总结

错误	正确	原因
Does she likes coffee?	Does she like coffee?	does 后动词原形
Did you went?	Did you go?	did 后动词原形
I don't am tired.	I am not tired.	be 动词不用 do
She doesn't can swim.	She can't swim.	情态动词不用 do
Do he like English?	Does he like English?	第三人称单数用 does
They don't finishes.	They don't finish.	do 后动词原形

✅ 一句话总结

Do / Does / Did 是助动词，用来构成疑问、否定、强调；后面永远跟动词原形。Be 动词和情态动词不用它们。

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