CONDITIONAL SENTENCES

Conditional Sentences are also known as Conditional Clauses or If Clauses. They are used to express that the action in the main clause (without if) can only take place if a certain condition (in the clause with if) is fulfilled. Conditional sentences are sentences expressing factual implications, or hypothetical situations and their consequences. They are so called because the validity of the main clause of the sentence is conditional on the existence of certain circumstances, which may be expressed in a dependent clause or may be understood from the context. A full conditional sentence (one which expresses the condition as well as its consequences) therefore contains two clauses: the dependent clause expressing the condition, called the protasis; and the main clause expressing the consequence, called the apodosis.

Conditional tenses are used to speculate about what could happen, what might have happened, and what we wish would happen. In English, most sentences using the conditional contain the word if. Many conditional forms in English are used in sentences that include verbs in one of the past tenses. This usage is referred to as "the unreal past" because we use a past tense but we are not actually referring to something that happened in the past.  There are five main ways of constructing conditional sentences in English. In all cases, these sentences are made up of an if clause and a main clause.In many negative conditional sentences, there is an equivalent sentence construction using "unless" instead of "if".

Types Of Conditional Sentences

THE ZERO CONDITIONAL

The zero conditional is used for when the time being referred to is now or always and the situation is real and possible. The zero conditional is often used to refer to general truths. The tense in both parts of the sentence is the simple present. In zero conditional sentences, the word "if" can usually be replaced by the word "when" without changing the meaning.

From:

If + Simple Present, + Simple Present

Examples:

If you run, you sweat.

If I drink a lot of alcohol, I get a hangover.

If it’s icy, the floor is slippery.

TYPE 1 CONDITIONAL

The type 1 conditional is used to refer to the present or future where the situation is real. The type 1 conditional refers to a possible condition and its probable result. In these sentences the if clause is in the simple present, and the main clause is in the simple future.

If clause                      Main clause

If + simple present      simple future

If this thing happens   that thing will happen.

If you don't hurry       you will miss the train.

If it rains today           you will get wet.

TYPE 2 CONDITIONAL

The type 2 conditional is used to refer to a time that is now or any time, and a situation that is unreal. These sentences are not based on fact. The type 2 conditional is used to refer to a hypothetical condition and its probable result. In type 2 conditional sentences, the if clause uses the simple past, and the main clause uses the present conditional.

If clause               Main clause

If + Past tense      would + verb

If I had time         I would drop you off at school.

If I had wings       I would fly.

TYPE 3 CONDITIONAL

The type 3 conditional is used to refer to a time that is in the past, and a situation that is contrary to reality. The facts they are based on are the opposite of what is expressed. The type 3 conditional is used to refer to an unreal past condition and its probable past result. In type 3 conditional sentences, the if clause uses the past perfect, and the main clause uses the perfect conditional.

If clause                                             Main clause

If + Past Perfect tense                        would have + past participle

If I had known about his condition, I would have phoned for you earlier.

If we had known about the storm, we wouldn't have started our journey.

Another Way to Explain Conditional Sentences

You have probably noticed that different teachers, textbooks, and Web sites sometimes explain the same thing in different ways. This seems to be especially true of conditional sentences. However, two different explanations can both be correct, especially if the difference is due to the fact that complicated material has been organized in different ways. This is often true of explanations of conditionals that you find in your textbooks. Here conditional sentences are divided into three types based on their meanings: real, predictive, and imaginative conditional sentences.

A. Real conditional sentences can express generalizations and inferences.

1. Generalizations include facts that are always true and never change, and they include present or past habitual activities that are or were usually true.

Examples of real conditional sentences expressing facts:

If water boils, it turns to steam.

2. Inferences are often expressed in real conditional sentences.

Real conditionals expressing inferences usually have parallel verb phrases in both clauses. However, if a modal which explicitly expresses an inference (must or should, for example) is used in the main clause, parallel verb phrases are not used.

Examples of real conditional sentences expressing inferences:

If today is Wednesday, it is George’s birthday.

B. Predictive conditional sentences can express predictions and plans.

1. Predictive conditional sentences usually contain simple present tense in the if-clause and will or be going to in the result clause. However, a weaker modal of prediction (may or should, for example) can be used in the result clause to express less certainty.

2. Examples of predictive conditional sentences:

If the exam is hard, many students are going to fail.

C. Imaginative conditional sentences are the most difficult for many learners of English because of the unusual relationship between form (the tenses used) and meaning. In this type of conditional sentence, past tense refers to present or future time; past perfect tense refers to past time. Another problem for many learners of English is that were (not was) is used with singular subjects. Be is the only English verb with two past tense forms, but only one of them (were) is used in imaginative conditional sentences.

Imaginative conditional sentences can express hypothetical or contrary-to-fact events or states.

1. Hypothetical events or states are unlikely but possible in the present or future. Imaginative conditional sentences expressing hypothetical events or states have a past tense verb in the if-clause and would + verb (or might or could + verb) in the result clause.

Examples of hypothetical conditional sentences (present and/or future time):

If George had enough money, he would buy a new car.

If I won the lottery, I would buy you a present.

If she knew the answer, she would tell us.

(George probably does not have enough money; I probably will not win the lottery; she probably does not know the answer.)

2. Contrary-to-fact events or states are either impossible in the present time or did not happen in the past. Imaginative conditional sentences expressing present contrary-to-fact events or states have a past verb in the if-clause and would + verb (or might or could + verb) in the result clause. 

Examples:

If I were you, I would not do that.

If she studied for exams, she would get better grades.

If it were raining, the streets would be wet.

(I am not you; she doesn’t study for exams; it isn’t raining.)

Imaginative conditional sentences expressing past contrary-to-fact events or states have a past perfect verb in the if-clause and would + have + verb (or might or could + have + verb) in the result clause. 

Examples:

If George had had enough money, he would have bought a new car.

If I had won the lottery, I would have bought you a present.

If she had known the answer, she would have told us.

(George did not have enough money; I did not win the lottery; she did not know the answer.)

Functions of Conditional Sentences

TYPE 1

The type 1 conditional refers to a possible condition and its probable result. These sentences are based on facts, and they are used to make statements about the real world, and about particular situations. We often use such sentences to give warnings. In type 1 conditional sentences, the time is the present or future and the situation is real.

Example:

If I have time, I'll finish that letter.

If you don't leave, I'll call the police.

In type 1 conditional sentence, you can also use modals in the main clause instead of the future tense to express the degree of certainty, permission, or a recommendation about the outcome.

Example:

If you drop that glass, it might break.

If you buy my school supplies for me, I will be able to go to the park.

TYPE 2

The type 2 conditional refers to an unlikely or hypothetical condition and its probable result. These sentences are not based on the actual situation. In type 2 conditional sentences, the time is now or any time and the situation is hypothetical.

Example:

If I was the Queen of England, I would give everyone a chicken. (But I am not the Queen.)

It is correct, and very common, to say "if I were" instead of "if I was" (subjunctive mood).

In type 2 conditional sentences, you can also use modals in the main clause instead of "would" to express the degree of certainty, permission, or a recommendation about the outcome.

Example:

We might buy a larger house if we had more money

He could go to the concert if you gave him your ticket.

If he called me, I couldn't hear.

TYPE 3

The type 3 conditional refers to an impossible condition in the past and its probable result in the past. These sentences are truly hypothetical and unreal, because it is now too late for the condition or its result to exist. There is always some implication of regret with type 3 conditional sentences. The reality is the opposite of, or contrary to, what the sentence expresses. In type 3 conditional sentences, the time is the past and the situation is hypothetical.

Example:

If I had worked harder I would have passed the exam. (But I didn't work hard, and I didn't pass the exam.)

If I had known you were coming I would have baked a cake. (But I didn't know and I didn't bake a cake.)

In type 3 conditional sentences, you can also use modals in the main clause instead of "would" to express the degree of certainty, permission, or a recommendation about the outcome.

Example :

If I had worked harder I might have passed the exam.

If he called you, you could go.

Exercises (Fill in the blank)

 If  Clauses, type 1. Complete the sentences.

1. If it (rain)  , we (stay)       at home.
2. If you (know/not)   the way, I (pick)    you up.
3. My mum (bake)    a cake if you (come)   to see us.

 If  Clauses, type 2. Complete the sentences.

1.        If you (study)   harder, you (get)   better marks in your tests.
2.        If I (be)   rich, I (travel)    around the world.
3.       She (come)  to the market with us if she (have/not)   to work.

 If  Clauses, type 3. Complete the sentences.

1.        If you (help)  us, we (finish)   the work in next to no time.
2.        I (call)    you earlier if I (lose/not)   your phone number.
3.       They (go/not)  to the theatre by car if the weather (be)     better.

 If  Clauses, mixed. Complete the sentences.

1.        If I (have)   a compass, I would give it to you.
2.        If he hadn’t been ill, he (run)  the marathon.
3.        If you go to Ireland, you (need)  a raincoat.
4.        We (miss/not) the train if we had got up earlier.
5.        If we lived in the country, the kids (play)  outside all day long.
6.        If they (eat/not)  that much, they wouldn’t have got a stomach ache.
7.        I will not be able to write you if you (give/not)   me your address.

Answers

 If Clauses, type I. Complete the sentences.

1.        If it rains, we will stay at home.
2.        If you do not know the way, I will pick you up.
3.        My mum will bake a cake if you come to see us.

 If  Clauses, type II. Complete the sentences.

1.       If you studied harder, you would get better marks in your tests.
2.       If I were rich, I would travel around the world.
3.      She would come to the market with us if she did not have to work.

 If  Clauses, type III. Complete the sentences.

1.        If you had helped us, we would have finished the work in next to no time.
2.        I would have called you earlier if I had not lost your phone number.
3.      They would not have gone to the theatre by car if the weather had been better.

 If  Clauses, mixed. Complete the sentences.

1.        If I had a compass, I would give it to you.
2.        If he hadn’t been ill, he would have run the marathon.
3.        If you go to Ireland, you will need a raincoat.
4.       We would not have missed the train if we had got up earlier.
5.       If we lived in the country, the kids would play outside all day long.
6.      If they had not eaten that much, they wouldn’t have got a stomach ache.
7.       I will not be able to write you if you do not give me your address.

Sources :

https://www.ego4u.com/en/cram-up/grammar/conditional-sentences

https://en.wikipedia.org/wiki/Conditional_sentence

http://grammar.ccc.commnet.edu/grammar/conditional2.htm

https://english.lingolia.com/en/grammar/sentences/if-clauses/exercises

http://www.edufind.com/english-grammar/conditional/

https://www.tesol-direct.com/guide-to-english-grammar/conditional-sentences
http://faculty.deanza.edu/flemingjohn/stories/storyReader$18