Modal Verbs Study Guide

1. Can

Present Tense
Usage: Ability, permission, and possibility.
Structure: can + base form of the verb
Examples:

I can swim. (Ability)
Can I use your phone? (Permission)
It can rain tomorrow. (Possibility)

Past Tense
Usage: Ability in the past.
Structure: could + base form of the verb
Examples:

I could swim when I was a child.
She could speak French when she lived in Paris.

2. Should

Present Tense
Usage: Advice, recommendations, and expectations.
Structure: should + base form of the verb
Examples:

You should see a doctor. (Advice)
The train should arrive on time. (Expectation)

Past Tense
Usage: Criticism or regret about past actions.
Structure: should have + past participle
Examples:

You should have called me earlier. (Criticism)
I should have studied harder for the exam. (Regret)

3. Would

Present Tense
Usage: Polite requests, habitual actions, and hypothetical situations.
Structure: would + base form of the verb
Examples:

Would you please pass the salt? (Polite request)
When I was young, I would visit my grandparents every summer. (Habitual action)
I would go if I were you. (Hypothetical situation)

Past Tense
Usage: Polite requests and hypothetical situations in the past.
Structure: would have + past participle
Examples:

I would have helped if I had known. (Hypothetical situation in the past)
She would have called if she had the number. (Polite past request)

4. Must

Present Tense
Usage: Necessity, strong recommendation, and logical deduction.
Structure: must + base form of the verb
Examples:

You must wear a seatbelt. (Necessity)
This must be the right answer. (Logical deduction)

Past Tense
Usage: Necessity or logical deduction in the past.
Structure: must have + past participle
Examples:

She must have forgotten about the meeting. (Logical deduction)
You must have studied hard for the exam. (Deduction)

5. Ought To

Present Tense
Usage: Moral obligation and advice.
Structure: ought to + base form of the verb
Examples:

You ought to apologize. (Moral obligation)
He ought to see a doctor. (Advice)

Past Tense
Usage: Criticism or regret about past actions.
Structure: ought to have + past participle
Examples:

You ought to have apologized. (Criticism)
She ought to have been more careful. (Regret)

6. Need To

Present Tense
Usage: Necessity and obligation.
Structure: need to + base form of the verb
Examples:

You need to finish your homework. (Necessity)
We need to leave now. (Obligation)

Past Tense
Usage: Necessity or obligation in the past.
Structure: needed to + base form of the verb
Examples:

I needed to call him yesterday. (Past obligation)
She needed to find a new job. (Past necessity)

7. Had Better

Present Tense
Usage: Strong advice or warning.
Structure: had better + base form of the verb
Examples:

You had better finish your work. (Strong advice)
She had better take an umbrella. (Warning)

Past Tense
Usage: Advising or warning about past actions.
Structure: had better have + past participle (rarely used)
Examples:

He had better have completed the report on time. (Past advice)

Summary Table

		Modal VerbPresent UsagePast Usage
Can	Ability, permission, possibility	Ability in the past (could)
Should	Advice, recommendations, expectations	Criticism, regret (should have)
Would	Polite requests, habitual actions, hypotheticals	Polite past requests, hypothetical past (would have)
Must	Necessity, strong recommendation, deduction	Necessity or deduction in the past (must have)
Ought To	Moral obligation, advice	Criticism, regret (ought to have)
Need To	Necessity, obligation	Necessity or obligation in the past (needed to)
Had Better	Strong advice, warning	Advising or warning about past actions (rare)

Practice Examples

Can
- She (can) speak three languages.
- I (could) swim when I was younger.
Should
- You (should) take an umbrella.
- He (should have) apologized earlier.
Would
- I (would) help if I could.
- She (would have) attended if she had known.
Must
- You (must) wear a helmet.
- They (must have) arrived by now.
Ought To
- You (ought to) try the new restaurant.
- He (ought to have) called you.
Need To
- We (need to) finish this today.
- I (needed to) get more information.
Had Better
- You (had better) see a doctor.
- She (had better have) completed the report.

Modal Verbs

Definition

Modal verbs are auxiliary verbs that express necessity, possibility, permission, ability, or obligation. They modify the mood of the main verb.

Common Modal Verbs

Can - ability or possibility
- Example: She can swim.
Could - past ability or polite request
- Example: I could read when I was three.
May - permission or possibility
- Example: You may leave early.
Might - slight possibility
- Example: It might rain later.
Must - necessity or strong obligation
- Example: You must wear a seatbelt.
Shall - future action (formal)
- Example: I shall return.
Should - advice or recommendation
- Example: You should see a doctor.
Will - future intention or promise
- Example: I will help you.
Would - polite request or hypothetical situation
- Example: Would you like some coffee?

Key Characteristics

No Infinitive Form: Modal verbs do not have an infinitive form (e.g., to can is incorrect).
No -s Form: They do not take an -s in the third person singular (e.g., he can not he cans).
Followed by Base Form: They are always followed by the base form of the main verb (e.g., can go, not can goes).

Usage

Expressing Ability: "She can play the piano."
Making Requests: "Could you help me?"
Giving Advice: "You should study for the exam."
Expressing Obligation: "You must finish your homework."
Indicating Possibility: "It might be true."

Negative Forms

Formed by adding "not" after the modal verb.
- Example: "You must not smoke."

Questions

Formed by inverting the subject and the modal verb.
- Example: "Can you come to the party?"

Conclusion

Modal verbs are essential for expressing various shades of meaning in English.