Expressing Condition

Unless

Unless

1. What it means

Unless is a linking word meaning except if or if … not. It introduces the only circumstance in which the result will not happen.

• You will fail **unless** you work harder.

= You will fail if you do not work harder.

• I won't forgive him **unless** he apologises.

= I won't forgive him if he does not apologise.

2. The golden rule

> Unless already contains the negative. Never add a second one.

| Wrong | Right | | :--- | :--- | | Unless you don't hurry, you will be late. | Unless you hurry, you will be late. | | Unless he doesn't study, he will fail. | Unless he studies, he will fail. |

This double negative is the single most frequent mistake with *unless*, and the exam tests it every year.

3. Turning *if not* into *unless*

To rewrite a sentence, remove the negative and replace *if* by *unless*.

| With *if … not* | With *unless* | | :--- | :--- | | If you do not revise, you will fail. | Unless you revise, you will fail. | | If she does not leave now, she will miss the bus. | Unless she leaves now, she will miss the bus. | | If they do not pay, the service will stop. | Unless they pay, the service will stop. |

4. Two values of *unless*

• **Condition**: *I won't forgive him unless he apologises.*
• **Warning or threat**: *You will fail unless you work harder.* The speaker is not describing a possibility but giving a warning.

5. Tense and punctuation

The rule is the same as for the other conditional conjunctions:

> unless + present simple, will + stem in the result.

And when *unless* opens the sentence, a comma separates the two clauses:

> Unless you get up early, you will be late. > You will be late unless you get up early.

6. *Unless* and *as long as* compared

They are close but opposite in shape:

• *as long as* states the condition **for** the result: *You will pass **as long as** you revise.*
• *unless* states the condition **against** it: *You will fail **unless** you revise.*

Both sentences describe the same situation.

7. Practice

A. Rewrite using *unless*.

• If you do not hurry, you will miss the train.
• If he does not stop smoking, his health will get worse.
• I will not come if you do not invite me.

B. Find and correct the mistake.

• Unless you don't revise, you will not succeed.
• Unless it will rain, we will play outside.
• Unless he apologise, I won't forgive him.

C. Rewrite with *as long as* without changing the meaning.

• You will not succeed unless you work hard.
• The engine will not start unless you fill the tank.

The Four Conditional Types

The Four Conditional Types

1. The table to memorise

| Type | *If* clause | Result clause | Use | | :--- | :--- | :--- | :--- | | 0 | If / When + present simple | present simple | A general truth, a scientific law. | | I | If + present simple | will + stem | A probable condition in the future. | | II | If + past simple | would + stem | Unreal, imagined, improbable. | | III | If + past perfect | would have + past participle | Regret about the past; it is too late. |

2. Type 0 — general truth

> If you boil water, it evaporates. > If you heat metal, it expands. > When the Sun sets, the temperature falls.

Here *if* and *when* are interchangeable, because the result always follows.

3. Type I — a probable future

> If you eat too much, you will put on weight. > If it rains tomorrow, we will stay at home.

The condition is realistic. Never write *will* in the *if* clause: *If it will rain* is wrong.

4. Type II — unreal or improbable

> If he went to an art school, there would be no guarantee of a job afterwards. > If I had a car, I would drive to work. > If I were you, I would stop smoking.

Two points the exam tests:

• with the verb *to be*, type II uses **were** for every person: *If I **were**…*, *If he **were**…*;
• *would* never appears in the *if* clause.

5. Type III — regret about the past

> If I had revised harder, I would have passed the exam. *(but I did not revise, and I failed)* > If they had left earlier, they would not have missed the plane.

Type III always describes something that cannot be changed. It is the grammar of regret, and it goes naturally with *I wish + past perfect*.

6. Reading the meaning behind the type

The type chosen tells the reader what the speaker thinks.

| Sentence | What it means | | :--- | :--- | | If I have time, I will call you. | I probably will have time. | | If I had time, I would call you. | I do not have time. | | If I had had time, I would have called you. | It is over; I did not call. |

7. Practice

A. Put the verbs into the right form.

• If water ______ (reach) 100 °C, it ______ (boil).
• If you ______ (revise) regularly, you ______ (pass) your exam.
• If I ______ (be) rich, I ______ (build) a school in my village.
• If she ______ (listen) to my advice, she ______ (not fail) last year.

B. Name the type of each sentence.

• If the government punished corrupt people, corruption would decrease.
• If you mix blue and yellow, you get green.
• If he had told the truth, nobody would have been angry.
• If it rains, the match will be postponed.

C. Rewrite as a type III sentence.

• He did not revise, so he failed.
• They arrived late, so they missed the beginning.

Suppose, Supposing, What If and Imagine

1. Making suppositions

When we speculate about space travel, life on other planets or the future of science, we often begin with an imaginary situation. Besides if, English has four expressions that open a supposition:

| Expression | Example | | :--- | :--- | | suppose (that) | Suppose you lived on the Moon, what would you miss most? | | supposing (that) | Supposing a satellite fell out of orbit, where would it land? | | what if | What if a large asteroid hit the Earth? | | imagine (that) | Imagine you were an astronaut on a six-month mission. |

All four work like if: the tense of the verb that follows tells the reader whether the speaker sees the situation as possible or as imaginary.

2. The tense decides the meaning

| Tense after the expression | Meaning | Example | | :--- | :--- | :--- | | present simple | a real possibility (the logic of type I) | What if the rocket is late? We will miss the launch window. | | past simple | an imaginary or unlikely situation (type II) | Suppose humans lived on Mars, how would they breathe? | | past perfect | a past situation that did not happen (type III) | Supposing the engineers had not checked the tank, what would have happened? |

With the verb to be, careful English uses were for every person in the imaginary case: *Suppose I were the captain of the spaceship…*

3. Two common patterns

A. A question on its own. *What if* is often used alone, with no result clause. It means *What will happen if…?* or *What would happen if…?*

> What if the satellite stops working? *(a real risk)* > What if there were no Moon? *(a pure hypothesis)*

B. A supposition followed by a result or a question.

> Supposing we found water on Mars, we could grow plants there. > Imagine you had a telescope at home: which planet would you look at first?

Note one more use of *suppose*: in conversation, *Suppose we take a break?* is a polite suggestion, close to *Why don't we take a break?*

4. Rewriting with *if*

| With suppose / what if | With if | | :--- | :--- | | Suppose you won a trip into space, would you accept? | If you won a trip into space, would you accept? | | What if the engine failed? | What would happen if the engine failed? | | Supposing the probe had landed safely, we would have received images. | If the probe had landed safely, we would have received images. |

5. The mistakes to avoid

| Wrong | Right | Why | | :--- | :--- | :--- | | Suppose humans would live on Mars… | Suppose humans lived on Mars… | No *would* after the expression. | | Supposing you will go to the Moon… | Supposing you go / went to the Moon… | No *will* either. | | What if he had came earlier? | What if he had come earlier? | Past perfect = *had* + past participle. | | Imagine you was an astronaut. | Imagine you were an astronaut. | *Were* in the imaginary case. |

6. Practice

A. Put the verb in brackets into the right form.

• Suppose you ______ (can) travel to any planet, which one would you choose?
• What if the Sun ______ (stop) shining?
• Supposing the astronauts ______ (not / return) safely, the mission would have been a disaster.

B. Rewrite with *if*.

• Imagine you had a spaceship. Where would you go?
• What if the launch is postponed?

C. Write three questions beginning with *What if* about life in space.

Practice and Review

Practice and Review

1. One situation, five ways to say it

Take the same idea and express it with each structure. This is exactly what a rewriting question asks.

> *Situation: you revise → you pass.*

• **Providing that** you revise, you will pass.
• You will pass **as long as** you revise.
• You will **not** pass **unless** you revise.
• **If** you revise, you will pass. *(type I)*
• **If** you revised, you would pass. *(type II, less probable)*

2. The mistakes the exam hunts

| Mistake | Correction | | :--- | :--- | | Unless you don't work, you will fail. | Unless you work, you will fail. | | If it will rain, we will stay in. | If it rains, we will stay in. | | Providing that you will ask me… | Providing that you ask me… | | If I was you, I would leave. | If I were you, I would leave. | | If he would have come, we would have started. | If he had come, we would have started. | | As long as you revise. you will pass. | As long as you revise, you will pass. |

3. Mixed exercise

A. Complete with the correct form.

• Unless the company ______ (change) its policy, consumers ______ (boycott) it.
• If scientists ______ (discover) a vaccine earlier, thousands of lives ______ (be) saved.
• You can borrow my dictionary provided that you ______ (give) it back tomorrow.
• If a comet ______ (hit) the Earth, it ______ (create) an enormous crater.

B. Join with the connector in brackets.

• The country will develop. / Corruption is fought. *(as long as)*
• You will not understand the text. / You read it twice. *(unless)*
• We will buy the product. / The label is clear. *(provided that)*

C. Rewrite without changing the meaning.

• If you do not check the expiry date, you may buy a dangerous product.

→ Unless

• You will succeed only if you work hard.

→ As long as

• He did not listen to the warning, so he had an accident.

→ If he

4. Answers to check yourself

A. 1. does not change / will boycott — 2. had discovered / would have been — 3. give — 4. hit / would create.

B. 1. The country will develop as long as corruption is fought. — 2. You will not understand the text unless you read it twice. — 3. We will buy the product provided that the label is clear.

C. 1. Unless you check the expiry date, you may buy a dangerous product. — 2. As long as you work hard, you will succeed. — 3. If he had listened to the warning, he would not have had an accident.