Grammar Essentials (Handbook)

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Modals, conditionals and the subjunctive

⏱ 5 min read🧩 7 question types🎯 12 practice Q

The idea in one minute

Modal verbs like can, may, must and should add a shade of meaning to the main verb. A conditional sentence joins an if clause to a result clause. The exam tests two things: the form after a modal, and the matching of tenses in a conditional.

What modals do

The modals are can, could, may, might, will, would, shall, should, must, ought to, need, dare, used to. Three facts hold for all of them.

A modal is followed by the base form of the verb: She can swim. Never She can swims or can to swim.
A modal takes no -s in the third person: He must go.
To make a question, put the modal first: Can you help?

Watch: Ought to and used to keep to. You ought to go. But after must, can, may, should there is no to.

Meanings

Modal	Use	Example
can / could	ability; could is past ability or polite request	He can drive. Could you help me?
may / might	permission; possibility (might is weaker)	May I come in? It might rain.
must	strong duty; strong logical certainty	You must wear a helmet.
have to	outside rule; needs tense forms	I had to leave early.
should / ought to	advice, moral duty	You should sleep early.
need	necessity; in questions and negatives it can act as a modal	You need not come. Need I come?
dare	courage; modal in negatives and questions	He dare not speak.
will / shall	future; shall with I and we for offers	Shall I open the window?
would	past habit, polite request	He would visit every summer.
used to	past habit or state, now stopped	I used to smoke.

Modals with the perfect

should have / ought to have + V3: a duty not done. You should have called.
could have + V3: a chance that was missed. She could have won.
must have + V3: a certain guess about the past. He must have missed the train.
may / might have + V3: a possible guess about the past. They might have left.
needn't have + V3: did it, but it was not needed. You needn't have come.
would have + V3: the result clause of a past unreal condition.

Conditionals

Type	If-clause	Result clause	Sense
Zero	present simple	present simple	general truth: If you heat ice, it melts.
First	present simple	will / can / may + base	real future: If it rains, we will stay.
Second	past simple (were for all subjects)	would / could / might + base	unreal present: If I were rich, I would travel.
Third	past perfect	would have + V3	unreal past: If she had studied, she would have passed.

Use were for all persons in a second-conditional if-clause: If I were you.
Do not use will or would in the if-clause itself. If it rains is right; If it will rain is wrong.
Unless = if not, and it already carries the negative: Unless you hurry, you will miss it.
Inverted forms drop if: Had I known, I would have come. Were he here, he would help. Should you need help, call me.
Wish takes the past for the present and the past perfect for the past: I wish I knew. I wish I had gone.
As if / as though with an unreal situation takes the past: He talks as if he owned the place.

Tip: In a third conditional both halves look back. If either half looks forward or present, the tense is wrong.

Question types you will see

Each type: how to recognise it, the method step by step, and one question to try.

Type 1very common3 practice Q

Modal + base form

How to spot it:

The sentence has can, may, must, should or will, and the next verb has -s, -ing, -ed or a to.

Method

Find the modal.
Look at the verb right after it.
If it is not the bare verb, that is the error.

Why it works:

Modals are helper verbs and carry the tense, so the main verb stays bare.

Try this

She can ___ five languages. (speaks / speak / speaking / to speak)

Show solution

The modal is 'can'.
The verb after it must be bare: 'speak'.

Answer

speak

Type 2common2 practice Q

Shades of meaning

How to spot it:

The blank sits in a sentence expressing duty, advice, permission, ability or a guess.

Method

Name the meaning: strong duty, advice, permission, ability, guess.
Match it: must, should, may, can, might.
Choose the modal for that meaning.

Why it works:

Each modal has one main job, and the stem tells you which job is needed.

Try this

You ___ wear a seat belt; it is the law. (must / might / could / would)

Show solution

The law is a strong duty.
Strong duty takes 'must'.

Answer

must

Type 3common3 practice Q

Modal + have + V3

How to spot it:

The sentence talks about the past and the options include should have, must have, could have, needn't have.

Method

Find the clue: regret, certainty, missed chance or unneeded act.
Match: should have (duty), must have (certain guess), could have (chance), needn't have (not needed).
Choose the matching option.

Why it works:

The perfect form after a modal points back to a past event.

Try this

The road is wet, so it ___ rained last night. (must have / should have / would have)

Show solution

The wet road is a clue for a certain guess.
A certain guess about the past takes 'must have'.

Answer

must have

Type 4very common2 practice Q

Conditional tense matching

How to spot it:

The sentence has an if-clause and a blank in the result clause, or the reverse.

Method

Read the if-clause tense.
Present simple: will + base. Past simple: would + base. Past perfect: would have + V3.
Choose the option that matches.

Why it works:

Each conditional type pairs one if-tense with one result form.

Try this

If I ___ you, I would accept the offer. (am / was / were / be)

Show solution

The result has 'would', so this is a second conditional.
The if-clause takes 'were' for all persons.

Answer

were

Type 5common

Unless and inverted conditionals

How to spot it:

The sentence has unless, or starts with Had, Were or Should in place of if.

Method

Unless means if not, so keep the verb positive.
Had + subject + V3 means if + past perfect.
Should + subject + base means if + present.

Why it works:

Dropping if and inverting the subject gives the same meaning.

Try this

Unless you ___ hard, you will not pass. (study / do not study / will study / studied not)

Show solution

'Unless' already means 'if not'.
The verb must stay positive: 'study'.

Answer

study

Type 6common

Wish and as if

How to spot it:

The sentence has wish, as if or as though, and the situation is unreal.

Method

Present unreal wish: use the past (I wish I knew).
Past unreal wish: use the past perfect (I wish I had gone).
Use were for all persons in the unreal present.

Why it works:

The unreal situation moves one step back in time.

Try this

I wish I ___ the answer now. (know / knew / had known / will know)

Show solution

The wish is about the present.
The verb goes back one step: past 'knew'.

Answer

knew

Type 7occasional

Need, dare and used to

How to spot it:

The sentence has need, dare or used to in a negative, a question or a habit.

Method

Need and dare act as modals in negatives and questions, with no -s and no to.
Used to is a past habit that has stopped.
Check that the verb after it is bare.

Why it works:

These three verbs switch between modal and ordinary use.

Try this

You ___ come tomorrow; the meeting is cancelled. (needn't / don't need / needs not / need not to)

Show solution

'Needn't' works as a modal.
It is followed by a bare verb, so 'needn't come' is right.

Answer

needn't

Shortcuts that save time

⚡ Match the type by the if-clause

Read only the if-clause. Present simple: use will or can in the result. Past simple: use would in the result. Past perfect: use would have + V3.

Example

If he had left earlier, he ___ the train. (would catch / would have caught / will catch)

Show solution

The if-clause is past perfect.
That is a third conditional.
The result needs 'would have + V3': 'would have caught'.

Answer

would have caught

⚡ Modal + base form

After any modal the next verb is bare. If you see a modal followed by to, -s, -ing or -ed, that is the error. The only exceptions are ought to and used to.

Mistakes to avoid

Where most students lose marks on this subtopic.

Mistake 01

She can sings well.

She can sing well. A modal takes the base form.

Mistake 02

You must to go now.

You must go now.

Mistake 03

If it will rain, we will stay home.

If it rains, we will stay home.

Mistake 04

If I would have money, I would buy a car.

If I had money, I would buy a car.

Mistake 05

If I was you, I would apologise.

If I were you, I would apologise.

Mistake 06

Unless you do not work hard, you will fail.

Unless you work hard, you will fail.

Mistake 07

You needn't to come.

You needn't come.

Quick revision

Read this the night before the exam.

Modal + bare verb; no -s; no to (except ought to and used to).
must = duty or certainty; should = advice; may = permission or possibility.
should have + V3 = duty not done; must have + V3 = certain guess about the past.
First: if + present, will + base. Second: if + past, would + base. Third: if + past perfect, would have + V3.
Use were for all subjects in the second conditional.
No will or would inside the if-clause.
Unless = if not; do not add a second negative.

Practice: 12 questions

Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.

Topic test · 12 questions

Suggested time 6 min · wrong answers go to your mistake notebook automatically.

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