The 5 Types of Conditional Sentences

Conditional Sentences are also known as Conditional Clauses or If Clauses, they are used to speculate about what could happen, what might have happened, and what we wish would happen. The 5 types of conditional sentences in English are described below.
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”.
Note: 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.

The 5 Types of Conditional Sentences

1. Conditional Sentence Type 1
It is possible and also very likely that the condition will be fulfilled.
                   If-Clause (Condition)         Main Clause (Result)
 Form:     Simple Present                        Will-Future

• If i drink coffee tonight, I won’t sleep well.
• If i find her address, I will send her an invitation.
• I will send her an invitation if I find her address.

Function:
Conditional Sentences Type I refer to the future. An action in the future will only happen if a certain condition is fulfilled by that time. We don’t know for sure whether the condition actually will be fulfilled or not, but the conditions seems rather realistic – so we think it is likely to happen.

Using “Unless”
Unless means the same as if…not. Like if, unless is followed by a present tense, a past tense, or a past perfect tense (never by a conditional). Unless is used instead of if…not in conditional sentences of all types. The order of the clauses doesn’t matter with sentences using unless.

TYPE 1 CONDITIONAL: UNLESS + PRESENT TENSE
          With if                                                                                     Equivalent with unless

• You will be sick if you don’t stop eating.                                You’ll be sick unless you stop eating.
• I won’t pay if you don’t provide the goods immediately.        I won’t pay unless you provide the goods immediately.
• If you don’t study diligently, you’ll never understand trigonometry.
• Unless you study diligently, you’ll never understand trigonometry.

2. Conditional Sentence Type 2
 It is possible but very unlikely, that the condition will be fulfilled.
                 If-Clause (Condition)                Main Clause (Result)
Form:      If+ Simple past                           Would/Could + IV

• If I studied, I would pass the exam.
• If I were at home, I would watch television.
• I would send her an invitation if I found her address.

Were instead of Was
In IF Clauses Type II, we usually use ‚were‘ – even if the pronoun is I, he, she or it – We use it whenever we talk against the fact.

•  If I were you, I would not do this.
• If he were the president, he would bring changes.

Function:
Conditional Sentences Type II refer to situations in the present. An action could happen if the present situation were different. I don’t really expect the situation to change, however. I just imagine „what would happen if …“

TYPE 2 CONDITIONAL: UNLESS + PAST TENSE
   With if                                                                                             Equivalent with unless

• If he wasn’t very ill, he would be at work.                               Unless he was very ill, he would be at work.
• I wouldn’t eat that food if I wasn’t really hungry.                    I wouldn’t eat that food unless I was really hungry.
• She would be here by now if she wasn’t stuck in traffic.        She would be here by now unless she was stuck in traffic.

3. Conditional Sentence Type 3
 It is impossible that the condition will be fulfilled because it refers to the past.
              If-Clause (Condition)            Main Clause (Result)
Form: If+ Past perfect                        Would + Have + Past participle

• If I had found her address, I would have sent her an invitation.
• If Ali had won the match, he would have gone to final.
• If I had studied, I would have passed the exam.

Function:
Conditional Sentences Type III refer to situations in the past. An action could have happened in the past if a certain condition had been fulfilled. Things were different then, however. We just imagine, what would have happened if the situation had been fulfilled

TYPE 3 CONDITIONAL: UNLESS + PAST PERFECT
With if 

• Our director would not have signed the contract if she hadn’t had a lawyer present.
• I wouldn’t have phoned him if you hadn’t suggested it.
• They would have shot her if she hadn’t given them the money.

 Equivalent with unless

• Our director would not have signed the contract unless she had had a lawyer present.
• I wouldn’t have phoned him unless you’d suggested it.
• They would have shot her unless she’d given them the money.

4. 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.
In zero conditional sentences, the word “if” can usually be replaced by the word “when” without changing the meaning.
                If-Clause (Condition)          Main Clause (Result)
Form:   If + Simple present                Simple present

• If you heat ice, it melts.
• Ice melts if you heat it.
• When you heat ice, it melts.
• If it rains, the grass gets wet.

Function:
The zero conditional is used to make statements about the real world, and often refers to general truths, such as scientific facts. In these sentences, the time is now or always and the situation is real and possible.

5. Mixed Type Conditional
The mixed type conditional is used to refer to a time that is in the past, and a situation that is ongoing into the present. The facts they are based on are the opposite of what is expressed. The mixed type conditional is used to refer to an unreal past condition and its probable result in the present.

There are two types of mixed conditional sentence.

Present result of a past condition:            

 If-Clause (Condition)                    Main Clause (Result)
Form: If + past perfect                   present conditional

• If this thing had happened that thing would happen.
• If I had worked harder at school, I would have a better job now.
• I would have a better job now if I had worked harder at school.
• If we had looked at the map, we wouldn’t be lost.
• We wouldn’t be lost if we had looked at the map.

Function:
This type of mixed conditional refers to an unreal past condition and its probable result in the present. These sentences express a situation which is contrary to reality both in the past and in the present.

Past result of present or continuing condition:

               If-Clause (Condition)            Main Clause (Result)
Form:  If + simple past                        perfect conditional

• If this thing happened that thing would have happened.
• If I wasn’t afraid of spiders, I would have picked it up.
• I would have picked it up if I wasn’t afraid of spiders.
• If we didn’t trust him we would have sacked him months ago.
• If I wasn’t in the middle of another meeting, I would have been happy to help you.

Function:
These mixed conditional sentences refer to an unreal present situation and its probable (but unreal) pas result. In these mixed conditional sentences, the time in the if clause is now or always and the time in the main clause is before now.

As an illustration: “If I wasn’t afraid of spiders” is contrary to present reality. I am afraid of spiders. “I would have picked it up” is contrary to past reality. I didn’t pick it up.

Conclusion:

Was the article helpful? Please feel free to write you comment in the comment box below about the article. Indeed All Conditional Sentences In English  have a lot of uses in daily conversation, therefore it’s significant for ESL students to learn about it’s forms, clauses, tenses and functions to build their grammar accuracy.