Put the verbs in brackets into a suitable form.
(universal facts and habits: if [present], [present]
Fresh milk goes sour if you keep it for a long time.
If/Whenever I enter the house in muddy shoes, my wife (always) shouts at me.
If Mr Perkins (catch) someone napping, he always (make) them do twenty press-ups.
If you (put) a block of ice in the sun, it (melt).
If she (be) sad, she usually (listen) to Cat Stevens.
If the roads (be) wet, it (be) more dangerous to drive on them.
If it (rain), we never (go) for a ramble.
(imperatives: if [present], [present]
Don't do it if you feel/are feeling tired.
Take it easy if you don't want to have another relapse.
We do not mention the subject before the main verb in imperative sentences. For more details about imperative sentences, see unit 9, section 54
(not drive) if you (be) drunk. You could have an accident.
(not tell) her if you (not want) to.
If you (not be) busy, (help) me.
(not eat) it if you (be) full.
(not add) fuel to the flames if you (not want) to have a row with your wife.
(possible, probable or real: if [present], [will + infinitive]
If you follow my advice, you will not have any trouble with the Treasury.
If you (present) your proposal, we (see) what we can do about it.
If we (put) off the meeting now, when it (be) held again?
If you (let) me down again, I no longer (rely) on you.
If you (break) your promise, you (suffer) for it.
We (give) them a call if we (decide) to pay them a visit.
If a person smokes heavily, he or she can get lung cancer.
In place of will
, other modal verbs are possible.
He needn't come if he (have) many things to do.
If we (tell) them the whole truth now, they may forgive us.
We must leave now if we (want) to get there before dark.
If the weather (not improve), we should (or "ought to") stay at home.
We had better tell her everything if she (ask) us.
If you have finished with your housework, we can go to the theatre.
If this washing machine is not still working properly after all the money we have spent fixing it, we'd better buy a new one.
If you have been running for over an hour, it is not surprising that you should be tired out.
If everything goes well, I'll have finished by noon.
If I haven't retired earlier, I'll have been working for the same company for twenty years in November.
If we don't start now, we'll still be working at five o'clock.
Note that apart from the simple present and the future simple (will + infinitive
), we can have other verb forms.
If it (not snow) now, I (show) you round town.
If you (not finish) yet, you'd better stay at home and finish it.
If you (come) tomorrow at midday, I (cook) the dinner. Can you come a bit later?
If you (study) Chinese for five years, you should at least speak it.
If my memory (not deceive) me, we (be) married for forty-five years in May.
6 Revision exercise.
If you (be) bitten by a cobra, you can die from it, unless you take an antidote.
Water (boil) and (evaporate) if it (be) heated.
If you (be) exposed to the sun's rays for a long time, you (get) your skin burnt.
We'd better postpone the match if it still (rain).
We may go to Africa next winter if we (save) enough money by then.
I (lend) you the money providing that you (pay) me back by Monday.
I (stay) here with you so long as you (not make) a scene.
I (go) out with you on condition that you (pay) for the drinks.
Unless you (tell) the teacher's pet our intentions, everything (go) alright
Suppose you (see) a policeman. What you (do) then?
My mother (get) angry whenever I (arrive) home late.
If you (play) with fire, you can get burnt.
If you (not do) the chores yet, you'd better hurry up.
If you (pour) oil on the flames, they (sack) you. So, please don't.
If he (take) part in the race, he may win.
If the worst (come) to the worst, we (have) to repeat the year.
If you (talk) behind my back again, you (regret) it.
If you (want) to do it, you must do it off your own bat.
If you (take) care of my sister, I (reward) you for it.
If you (not mind), I'd like to repay you for your kindness.
How about going to the theatre tomorrow evening?
If you (happen) to run into her, please (tell) her to come over for dinner.
She (tell) me tomorrow whether she can come or not
(close) the window if you (be) cold.
If we (not preserve) nature, we (destroy) the humankind as well.
(not stick) your tongue out at Mr Smith if you (not want) to be gated for a week.
If you (hitch-hike) again, we (not give) you any pocket money for a month.
(unreal or improbable: if [past], [would + infinitive]
If I were you, I would/should (more formal) keep things quiet.
If I had the night off, I'd go to your stag party. But, you know, I'm a night watchman, and can't duck out of it.
If it weren't pouring down, we would go for a walk.
If I were rich, I wouldn't be working here.
If I (have) a time machine, time (be) in my hands.
If it (not rain) buckets, we (drop) in on him.
If I (be) in your place, I (leave) the phone off the hook.
If you (be) to take the post, what you (do)?
If the brakes of your car (fail), you (jump) out?
(impossible: if [past perfect], [would
have + past participle])
These batteries wouldn't have run down if you had recharged them.
If it hadn't been sleeting, we wouldn't have stayed at home.
If he hadn't been a spy, they wouldn't have been torturing him/If he hadn't been a spy, they wouldn't have tortured him.
Imposible conditionals refer to the past; the other types seen in the previous sections, to the present or future. See unit 9, section 42.
If it (not drizzle), we (take) the kids to the zoo.
If she (not overbid) us, we (buy) the prehistoric axe.
If we (not underbid) her, we (obtain) the prehistoric axe.
"If you (reset) your watch, you (not be) late,"
"Yes, you're right, but I forgot that the time had been changed."
If you (sit) under the overhanging branches of the plane tree, you (be) cooler. Why didn't you sit there?
If she had responded to treatment, she wouldn't be dead now.
If I hadn't twisted my ankle, I'd go with you this afternoon.
If you hadn't smoked like a chimney last night, you wouldn't be coughing now.
If you hadn't been eating, you would eat your dinner up now.
If [past perfect], [would + infinitive]
is used to link the present or the future to the past. It is also possible, though probably less common, to say if [past], [would have + past participle]
: They would have gone there if they were not ill
If you (not sling) your satchel on the mud, it (not be) so dirty. Now you'll have to wash it yourself with soap and water.
She was so angry that she rent her blouse in two. If she (not rend) it in two, she (use) it for tomorrow's party.
He's guilty in the eyes of the law, but only because he didn't tell all the truth. If he (not conceal) any facts of what occurred that night, now he (not be) regarded as one of the people implicated in the robbery.
He's lucky not to be here now. If he (be) here now, I (tell) him a few home truths.
They lent us the money we needed to continue with the business; if they (not come) to our rescue, we (not run) it now.
If you don't trust him, why have you offered him the job?
If you knew she was not faithful to you, why did you marry her?
in the above sentences means as
If you already (finish), why we (not take) the kids to the zoo?
If you (feel) dizzy, why you (not lie) down a bit?
If you (know) he was so pigheaded, why you (try) to convince him that he was wrong?
If you (be) so sure that she wouldn't be ready in a twinkle, why you (wait) for her? Why you (not tell) her to come here?
If you (realise) how smarmy she was, why you (believe) her?
If you should see a rattlesnake in your bedroom, don't kill it, as it's my pet.
The sentence above means that you are not very likely to see my snake in your bedroom. If we use should
in the conditional clause, we often use an imperative in the main clause. If we drop should
, we suggest a bigger probability.
If you (happen) to change your mind, please (let) us know.
If by any chance she (come) home, (tell) her to wait for me, would you?
If you (receive) another allowance from your parents, you must pay me back.
You didn't study, so I don't think she will let you through; but if she (let) you through, (ring) me up, please.
If you (come) across my wedding ring anywhere, please (telephone) me at once.
12 Revision exercise.
Your jacket is very creased. If you (sling) it over the back of the armchair, it (not crease).
"I overslept this morning."
"If you (set) your alarm clock as I told you last night, you (not oversleep)."
We were hidden behind a bush, but she saw a spider and shrieked with fright. If she (not shriek) with fright, they (not discover) us.
If I (be) in your shoes, I (not be) so meek and mild. I (be) tougher. This is what they deserve.
He scored five baskets in the first minutes of the second half, which spurred his team to victory. If he (not score) them, his team probably (not win) the game.
"Why don't you ask him to help you?"
"If he (not be) so angry with me, I __________.' (short answer)
"She felt light-headed after drinking two gins and tonic, so she went to bed."
"If she (not drink) any alcohol, she (not feel) light-headed, and (not have) to go to bed; and of course, she (be) here now."
My parents got very cross with me because we married in a registy office. If we (marry) in church, I (have) a very good dowry."
I don't think it'll rain, but if it (rain), (bring) the washing in, please.
He talked ill about you. If you (make) a good impression on him, he (not talk) ill about you.
"If you (not keep) this omelette in the fridge, it (spoil) in the heat."
"Don't worry! I'll put it in the fridge immediately."
If we (leave) now, we (reach) home in time to watch the match on telly.
I fell into the river and couldn't swim. But for her, I (drown).
I fell into the river and couldn't swim. But for her, I (be) dead now.
I hope you don't need any outside help; but if such (be) the case, you could always rely on us.
Does any of you want to work for us? If so, please (raise) your hands. If not, you can leave.
"I had the accident because I was exhausted."
"If you (be) exhausted, why you (not stop) the car and (sleep) a little bit?"
If I (tell) my mother a lie, she usually (find) out, so I won't tell her any.
(not make) promises if you can't keep them.
My father's lighter doesn't work because it hasn't got a flint. If it (have) one, it (work).
Her children are given to answering back. If she (not spoil) them so much, they (not do) such a thing.
If I (see) him, I (give) him a piece of my mind. What he's been doing is despicable.
"What (happen) if I hit this button?"
"If you (press) it, the machine (stop) working, so please don't."
"If you (not slow) up, you never (recover) from your illness."
"But, I can't, doctor: my business cannot be neglected!"
"Well, in that case, your illness will go from bad to worse, and in the near future you won't be able to work at all. If this (be) what you want, (not slow) up"
Why didn't you tell me you were coming. If I (know) you were coming, I (prepare) a special meal.
If I (not give) up my studies, I (be) an important lawyer now; but my father fell ill, and had to take up a job as a waiter.
is the most common conditional conjunction, but there are others, such as as/so long as, but for, on condition (that), provided/providing (that), suppose/supposing (that), unless, whenever, whether...(or not)
Unless it snows, we'll go on a ramble in the country.
If it doesn't snow, we'll go on a ramble in the country.
But for her, we wouldn't be alive now.
If it hadn't been for her, we wouldn't be alive now.
Suppose/Supposing (that) she betrayed you. What would you do (then)?
What if she betrays you?
What would you do if she betrayed you?/If she betrayed you, what would you do (then)?
cannot be used in the following cases:
-I don't know whether to sign the contract (or not). [whether + an infinitive]
-Everything will depend on whether we can earn enough money (or not). [a preposition + whether]
-Whether you do it or not is your responsibility. [Whether...or not is the subject.]
-It's your responsibility whether you do it or not.
[Another alternative to the one given above.]
-I'm not sure whether or not she'll come/I'm not sure whether/if (less formal) she'll come or not.
Note the difference between the next two sentences:
If you pass, please let me know.
(Only if you pass.)
Whether you pass or not, please let me know.
(Let me know anyhow.)
A future tense is also possible: Fresh milk will go sour if you keep it for a long time
We do not write a comma if we place the conditional clause after the main clause. However, if we invert the order, that is, if we put the conditional clause before the principal one, a comma is usually added:
I often have a nap if I'm tired after lunch.
If I'm tired after lunch, I often have a nap.
may be used instead of will
with the first persons (I, we):
If I have time, I shall/will call in on you/If I have
time, I'll call in on you.
is informal. In more formal language, all right
should be used.
Note that this is an indirect question. For indirect or reported speech, see unit 26
Instead of would
, other modal verbs in their conditional (or past) forms are possible:
If I had a car, I could
(= would be able to)/might
(= would probably)/should/would drop in on you every day.
If the rain weren't coming down in buckets, we could
(= would be able to)/might
(= would probably)/would/should arrive there by noon.
are interchangeable in the first persons (I, we), unless should
means ought to
. Note that there is a difference in meaning between could
. For modal verbs, see unit 22
is preferred to was
here. See also unit 9
, sections 55
In place of would
, other modal verbs in their conditional (or past) forms are possible: If she hadn't caught you cheating, you could/might have passed
. See the previous section (footnote).
Other modal verbs are possible: If the rain hadn't been falling in buckets, we could/might be there now
. See the previous sections (footnotes).