CONDITIONAL CLAUSES

FIRST CONDITIONAL CLAUSES (PROBABLE / LIKELY)  (Future Reference)

IF-CLAUSE: Present Simple   MAIN CLAUSE: Future Simple

EXAMPLE:  If you study, you will pass the test

                  If he does not work, he will not get any money

-          No difference if the clauses are reversed (except the comma): You will pass the test if you study.

-          If a question, the Main Clause always first: Will you pass the test if you study?

-          UNLESS is employed with the meaning IF NOT: Unless you study, you will not pass the test. (If you don't study, you won't pass the test).
-          If can be replaced by after, before, until, till, as soon as, when, once, by the time and the moment: After you read this, you will know the answer. 

USES:

·                    When the action of the If-Clause is expected to take place: If you take care of your shoes, they will last long enough (and you will probably take care of your shoes).

MODIFICATIONS:

·                    Present Simple Continuous in the If-Clause: If he is sleeping, I will kill him.

·                    Present Perfect Simple in the If-Clause: If she has found my dog, I'll reward her.

VARIATIONS:

·                    If the action of the If-Clause is more doubtful or unlikely, SHOULD + BASE can be used:

-          If it should rain, we shall stay home

-          If you should go, I shall be glad

·                    This construction is usually combined with the IMPERATIVE in the Main Clause:

-          If you should see the teacher, tell her I am ill

-          If you should go, do not say a word

·                    IMPERATIVE construction with CONDITIONAL meaning:

-          Do not move or I will shoot = If you move, I will shoot

-          Keep quiet and you will not get hurt = If you keep quiet, you won't get hurt
·  MODALS such as CAN, MAY, MUST... can be used:

-          If he comes in ten minutes, he can join us

TIME CLAUSES

(PROBABLE / LIKELY) (Future Reference)      

SUBORDINATE-CLAUSE: Present Simple MAIN CLAUSE: Future Simple

Instead of IF we use different conjunctions: As soon as / By the time / The moment (that) / as long as / until / when / before / after ...

EXAMPLES:

He will forgive you as long as you are honest

The situation will not improve until the government decides to act

SECOND CONDITIONAL CLAUSES   (IMPROBABLE / UNLIKELY)(Present Reference)

IF-CLAUSE: Past Simple                MAIN CLAUSE: Conditional Simple

EXAMPLE:  If you studied, you would pass the test

                  If he did not work, he would not get any money

-          No difference if the clauses are reversed (except the comma): You would pass the test if you studied.

-          If a question, the Main Clause always first: Would you pass the test if you studied?

-          UNLESS is employed with the meaning IF NOT: Unless you studied, you would not pass the test. (If you didn't study, you wouldn't pass the test).

USES:

·                    When the action of the If-Clause is not expected to take place: If she concentrated very hard, she would understand the whole lesson (but she will not probably concentrate very hard).

·                    When the assumption is different from the known facts: If I knew where the school is, I would immediately tell you (but I don't know where the school is).

MODIFICATIONS:

·                    Past Simple Continuous in the If-Clause: If he were teaching at the moment, he would be a great professor.

VARIATIONS:

·                    COULD / MAY / MIGHT + BASE can be used in the Main Clause when the action is still improbable but the possible result is being considered: We could / may / might watch tennis this noon if the teacher let us earlier.

·                    SUBJUNCTIVE of TO BE: the PAST of TO BE is employed as the second Conditional Clause (WERE is used with all subjects): If I were a rich man, I would be very happy.

·                    'IF I WERE YOU, I SHOULD / WOULD…' is a way of giving you a piece of advice: If I were you, I should take care.

THIRD CONDITIONAL CLAUSES       (IMPOSSIBLE)                                 (Past Reference)

IF-CLAUSE: Past Perfect Simple MAIN CLAUSE: Conditional Perfect Simple

EXAMPLE: If she had let you her car, you would have arrived on time.  

If I had known the pub was so far, I wouldn't have gone there.

-          No difference if the clauses are reversed (except the comma): You would have arrived on time if she had let you her car.

-          If a question, the Main Clause always first: Would you have arrived on time if she had let you her car?

-          UNLESS is employed with the meaning IF NOT: Unless she had let you her car, you would not have arrived on time

USES:

·                    When the action of the If-Clause is impossible to take place (when the events referred to are in the past and, therefore, the condition cannot be fulfilled yet: He would have been top of the class if he had worked harder (but he didn't work hard so, he is not and cannot be yet, top of the class).

MODIFICATIONS:

·                    Past Perfect Continuous in the If-Clause: If he had been listening, he would have heard the result.

VARIATIONS:

·                    COULD / MAY / MIGHT + BASE can be used in the Main Clause expressing ability and different degrees of possibility: If he had worked hard, he could / may / might have passed the test.