Grammar :                                               Conditional  Sentences : All Types

                                                                           (“if”sentences)

Introduction:

There are 4 main types of if sentences in English, often called conditional sentences. These sentences are in two halves (clauses):

Ø  the if part (if clause)

Ø the other part where you can use words such as can, will, may, might, could and would (main clause)

   

ZERO CONDITIONAL is a structure used for talking about general truths -- things which always happen under certain conditions (note that most zero conditional sentences will mean the same thing if "when" is used instead of "if"). The zero conditional is used to talk about things which are always true -- scientific facts, general truths, and so on.

if clause main clause If + Present Simple Present Simple If you heat the water to 100 degrees, it boils.

    1st CONDITIONAL is a structure used for talking about possibilities in the present or in the future. The first conditional is used to talk about things which are possible in the present or the future -- things which may happen.

if clause	main clause
If + Present Simple	Future Simple, can, may
If you study hard,	you will pass the test.

   2nd CONDITIONAL is a structure used for talking about unreal situations in the present or in the future. The second conditional is used to talk about things which are unreal (not true or not possible) in the present or the future -- things which don't or won't happen.

if clause	main clause
If + Past Simple	would, could, might
If I had a million dollars,	I would buy a big house.

  3rd CONDITIONAL is a structure used for talking about unreal situations in the past. The third conditional is used to talk about things which DID NOT HAPPEN in the past. If your native language does not have a similar construction, you may find this a little strange, but it can be very useful. It is often used to express criticism or regret.

if clause	main clause
If + Past Perfect	would/could/might have + Past Participle
If I had studied harder,	I would have passed the exam.

If the "if" clause comes first, a comma is usually used. If the "if" clause comes second, there is no need for a comma –

Water boils if you heat it to 100 degrees.

  You will pass the test if you study hard.

   I would buy a big house if I had a million dollars.

  I would have passed the exam if I had studied harder.