This document discusses the four types of conditional sentences in English: zero, first, second, and third conditional. It provides examples of each type and explains their uses. The zero conditional describes simple cause and effect or scientific truths. The first conditional expresses likelihood or promises/threats. The second conditional discusses unlikely or imaginary situations. The third conditional talks about impossible past situations or expresses regrets. It also covers alternatives to "if" such as "unless", "otherwise", and mixed conditionals.

1. CONDITIONAL SENTENCES
Zero
First
Second
Third

2. Use of conditional sentences
 Conditional
sentences allow us to talk about
POSSIBLE and IMPOSSIBLE/ UNREAL
SITUATIONS and their CONSEQUENCES.
 So, conditional sentences typically contain
TWO CLAUSES:
- a condition clause (if-clause)
- a result clause

3. ZERO CONDITIONAL:
if+ present simple, / present simple
Present simple / if+present simple
 To
describe A SIMPLE CAUSE AND
EFFECT
If you press that button, the engine starts
If I drink coffee in the afternoon, I don’t sleep
at night.
 To write a SCIENTIFIC TRUTH
If you mix oil and water, the oil floats

4. FIRST CONDITIONAL:
IF + PRESENT SIMPLE , WILL
WILL / IF+PRESENT SIMPLE
When we believe that something is LIKELY
(PROBABLE) TO HAPPEN:
If I have the money, I will buy a new car
You will pass your exams if you study hard

For PROMISES or THREATS:
If I go to America, I’ll send you a postcard
If you don’t do your homework, you won’t go out


5. SECOND CONDITIONAL:
IF+ SIMPLE PAST, WOULD/COULD/ MIGHT +
INFINITIVE
when we think that a situation is NOT VERY
LIKELY TO HAPPEN
If the students were more serious, they would have
better results
 for UNREAL or IMAGINARY SITUATIONS:
If I were the President of the USA, I would help poor
people all over the world
 for ADVICE:
If I were you, I would think about it
for POLITE REQUESTS:
Would you mind if I borrowed these CDs?


6. EXAMPLE OF POSSIBLE VARIATIONS
 If
you tried again, you might succeed.
 If
I knew her number, I could ring her up.

7. THIRD CONDITIONAL
IF+PAST PERFECT , WOULD/COULD/MIGHT HAVE
+PAST PARTICIPLE
To describe SITUATIONS THAT DIDN’T HAPPEN
in the past (IMPOSSIBLE)
If I had won the lottery, I wouldn’t have had financial
problems.
(= but I didn’t win the lottery and so I had financial
problems)
 To express REGRETS:
If you had bought me a diamond ring, I would have
loved you forever.
(= but you didn’t buy me one, so I stopped loving you!)


8. Examples of possible variations:
- If I had known you were coming, I could
have met you at the airport.
(I didn’t know you were coming, so I didn’t meet
you there)
- We might have passed our exams if we had
studied harder.
(We didn’t study hard, so we didn’t pass our
exams)

9. ALTERNATIVES OF IF: UNLESS
UNLESS (= IF NOT): examples
A) - We won’t go to the beach if it isn’t sunny
tomorrow.
- We won’t go to the beach unless it is sunny
tomorrow.
B)- Tom wouldn’t come to the party if you
didn’t tell him.
- Tom wouldn’t come to the party unless you
told him.

10. OTHERWISE
 OTHERWISE
(= if it doesn’t happen/ if it
didn’t happen/ it it hadn’t happen)
- Stop eating chocolate, otherwise you won’t
lose weight. (If you don’t stop eating,...)
-Her father pays her fees, otherwise she
wouldn’t be here. (If her father didn’t pay,..)
-He studied very hard, otherwise he wouldn’t
have had such good marks.
(If he hadn’t studied so hard,...)

11. OTHER ALTERNATIVES TO ..if
 AS
LONG AS / PROVIDED (THAT) / ON
CONDITION THAT....
I’ll lend you my books as long as / provided
that / on condition that you promise to
bring them back.
 INVERSIONS
Had I known that he was upset, I wouldn’t
have said anything.
 EVEN IF...
Even if I were a millionaire, I wouldn’t give him
any money.

12. MIXED CONDITIONALS
It combines the THIRD CONDITIONAL (in the
condition clause) with the SECOND
CONDITIONAL (in the result clause):
-If I hadn’t eaten that seafood, I wouldn’t feel
so awful now.
-If the weather had been fine last week, there
would be roses in the garden now.