To Be: Am, Is, Are – Usage in Identity and Condition Sentences
1. What is To Be?
In English grammar, to be is an auxiliary verb (helping verb) that functions as a link between the subject and information that describes it. To be does not show an action or activity, but rather shows the state, identity, or condition of the subject.
In the present tense (current time), to be has three main forms: am, is, and are. These three forms are used depending on the subject of the sentence.
💡 Key Point: To be is equivalent to "is" or "are" in English. It serves as a bridge between the subject and the word or phrase that describes it.
2. Types of To Be: Am, Is, Are
The choice of to be depends on the subject of the sentence. Here is the breakdown:
| To Be | Subject | Example |
|---|---|---|
| Am | I (First person singular) | I am a student. |
| Is | He, She, It, singular noun | She is beautiful. |
| Are | You, We, They, plural noun | They are happy. |
Am is only used with the subject I. Is is used for third-person singular subjects. Are is used for plural subjects and you.
3. Formula and Sentence Patterns
The basic pattern of sentences using to be is very simple:
Affirmative: Subject + To Be + Description (Noun/Adjective/Adverb)
Negative: Subject + To Be + not + Description
Question: To Be + Subject + Description + ?
The description here can be a noun (for identity), an adjective (for condition), or an adverb of place (for location).
4. Usage in Identity Sentences
Identity sentences are used to state who or what someone or something is. These sentences use to be followed by a noun or noun phrase.
Examples of Identity Sentences:
I am a teacher.
I have the occupation of a teacher.
He is a doctor.
His profession is that of a doctor.
They are students.
They are people who study.
My name is David.
The name I go by is David.
We are programmers.
We work as programmers.
Notice that after to be, identity sentences are always followed by a noun that explains who or what the subject is — such as a profession, name, nationality, or relationship.
5. Usage in Condition Sentences
Condition sentences are used to describe how something is — feelings, characteristics, physical condition, or current state. These sentences use to be followed by an adjective.
Examples of Condition Sentences:
I am happy.
I experience happiness.
She is tired.
She is in a state of fatigue.
The weather is cold.
The current temperature is low.
We are hungry.
We have a need for food.
The children are noisy.
The children are making a lot of noise.
⚠️ Key Difference: Identity sentences use a noun after to be (answering "what/who"), while condition sentences use an adjective after to be (answering "how/what is the state").
6. Affirmative, Negative, and Question Sentences
Each sentence with to be can be changed into three forms: affirmative, negative, and interrogative (question).
a. Affirmative Sentences
I am a student. → I have the role of student.
She is kind. → She possesses kindness.
You are smart. → You have intelligence.
b. Negative Sentences
Add not after to be:
I am not a student. → I do not have the role of student.
She is not kind. (She isn't kind.) → She does not possess kindness.
You are not smart. (You aren't smart.) → You do not have intelligence.
c. Question Sentences (Interrogative)
Move to be to the front of the subject:
Am I late? → Is there lateness on my part?
Is she a teacher? → Does she have the role of teacher?
Are they happy? → Do they possess happiness?
Contractions (Short Forms)
| Full Form | Short Form | Negative Short Form |
|---|---|---|
| I am | I'm | I'm not |
| He is | He's | He isn't |
| She is | She's | She isn't |
| It is | It's | It isn't |
| You are | You're | You aren't |
| We are | We're | We aren't |
| They are | They're | They aren't |
7. Common Mistakes to Avoid
Below are mistakes that students learning English commonly make:
❌ Wrong: "I is happy."
✅ Correct: "I am happy."
Reason: The subject "I" always takes "am".
❌ Wrong: "She are a doctor."
✅ Correct: "She is a doctor."
Reason: Third-person singular subjects (she/he/it) use "is".
❌ Wrong: "They is students."
✅ Correct: "They are students."
Reason: Plural subjects (they/we/you) use "are".
❌ Wrong: "I am agree."
✅ Correct: "I agree." (no to be)
Reason: "Agree" is a regular verb and doesn't need to be.
❌ Wrong: "The book is belong to me."
✅ Correct: "The book belongs to me."
Reason: Do not use to be before a regular verb.
💡 Remember: To be is NOT used with regular action verbs. To be is only used with nouns, adjectives, or adverbs of place.
8. Interactive Practice Exercises
Fill in the blanks with am, is, or are. Click the button to see the answer.
9. Conclusion
To be (am, is, are) is a crucial foundation in English grammar. Here's a summary of what to remember:
- •Am → only for the subject I
- •Is → for subjects he, she, it, and singular nouns
- •Are → for subjects you, we, they, and plural nouns
- •Identity sentences: To Be + noun (who/what)
- •Condition sentences: To Be + adjective (how/state)
By mastering these basic rules and practicing consistently, you will become increasingly proficient at using to be in everyday English conversation and writing.