When a subordinate clause, denoting a condition or an imagination, begins with ‘If’, then the subordinate clause is known as If clause.
That means, If clauses are used to denote conditions or imaginations.
If clause are in four types. They are ;
- If clause in zero condition.
- If clause in simple present tense.
- If clause in simple past tense.
- If clause in past perfect tense.
Let’s study its different types in detail.
If clause in zero condition.
This type always denotes a fact or universal truth.
In this type both If clause and the following main clause are always in simple present tense. This type is always restricted to show only conditions not imaginations.
eg: If the Sun rises in the East, It sets in the West.
If dogs see strangers, they bark loudly.
Here, we can see the if clauses and the following main clauses in the given examples are in simple present tense.
If clause in Simple present tense.
In this type, the If clause, that means the subordinate clause denoting a condition or an imagination, is in simple present tense. Then the verb form of the following main clause is ‘will/shall/may/can + V’ or ‘will/shall/may/can + be + V3′.
It can either be used in Active Voice or in Passive Voice. So all the types of If clause are to be studied in both voices.
Thus, here, the patterns of this type in both voices are as follows;
Active Voice :-
If + S + do/does + V + O, S + will/shall/may/can + V + O.
eg: If she sings well, she can impress everyone.
If they examine the room, they will surely find out it.
Passive Voice:-
If + O + is/am/are + V3 + by + S, O + will/ shall/ can/ may + be + V3 + by + S.
eg: If the room is examined by them, it will surely be found out by them.
If the students are given proper guidelines, great achievements can be brought by them.
It is to be noted that If clause and the main clause may not always be in the same voices. Sometimes it may be in different voices as given in the following example,
If you finish the job in time (A.V), you will be granted a special allowance (P.V.).
If clause in Simple past tense.
Here, If clause is in simple past tense and the verb form of the following main clause is ‘would/should/might/could + V’ or ‘would/should/might/ could + be + V3′.
The patterns of this type in both voices are as follows,
Active Voice:-
If + S + did + V + O, S + would/should/might/could + V + O.
eg: If Martin attended the meeting, he could meet Jancy.
Passive Voice :-
If + O + was/ were + V3 + by + S, O + would/should/might/could + be + V3 + by+ S.
eg: If the meeting was attended by Martin, Jancy could be met by him.
If clause in Past perfect tense.
In this type, while if clause is in past perfect tense, the verb form of the following main clause is ‘would/ should/might/could + have + V3 ‘ or ‘would/should/might/could + have + been + V3’.
This type in both voices are as shown below,
Active Voice:-
If + S + had + V3 + O, S + would/should/might/could + have + V3 + O.
eg: If he had driven the car carefully, he could have avoided the accident.
Passive Voice:-
If + O + had + been + V3 + by + S, O + would/ should/ might/ could + have + been + V3 + by + S.
eg: If the car had been driven carefully by him, the accident could have been avoided by him.
So we have studied what is If clause and its different types.