This document discusses conditional sentences and their different types. There are three main types of conditional sentences using "if" clauses: Type 1 uses present tense in the if-clause and will-future in the main clause to express likelihood. Type 2 uses past tense in both clauses to express unlikelihood. Type 3 uses past perfect in the if-clause and would have + past participle in the main clause to express impossibility. A "Type 0" conditional uses present tense in both clauses to express facts or certainties. The type of conditional depends on the tense used and determines the probability or possibility expressed in the sentence.

1. Clauses and Conditionals

2. What is a ‘conditional sentence’?
 A sentence discussing factual implications or
hypothetical situations and their
consequences.
 Full conditional sentences contain two
clauses: the condition and the result.
 Eg.) If I go to the mall (condition), I will buy a
pair of jeans (result).

3. Conditional Sentence
 The ‘result’ is the main clause and the ‘condition’ is a
subordinate (dependant) clause.
 The properties of the conditional clause (tense,
degree of probability) determine the properties of the
entire sentence.
 Conditional clauses usually begin with “if” or “unless”
– If you study, you will pass the exam.
– You won’t pass the exam unless you study.

4. Three types of “IF” clauses in
conditional sentences:
 Type 1: if + Simple Present, will-future
– Expresses something that is likely to happen
 Type 2: if + Simple Past, would +infinitive
– Expresses something that is not likely to happen
 Type 3: if + Past Perfect
– Expresses something that is impossible.

5. Type 1: if + Simple Present, will-future
 Type 1 expresses something that is likely to
happen.
 Eg. If I catch the bus, I will get to school on
time.
 The main clause can also be at the
beginning of the sentence:
 Eg. I will get to school on time if I catch the
bus.

6. Type 1: if + Simple Present, will-future
 Conditional sentences Type 1 refer to the future.
 An action in the future will only happen if a certain
condition is met.
 We don’t know for sure whether or not the condition
will be fulfilled, but the condition is realistic and
therefore likely to happen.
 It is likely that I will catch the bus and get to school
on time.

7. Type 2:
if + Simple Past, would + infinitive
 Type 2 expresses something that is unlikely
to happen.
 Eg. If I had the time, I would go to the show.
 The main clause can also be at the
beginning of the sentence:
 Eg. I would go to the show if I had the time.
 We usually use “were” instead of “was” in
Type 2.

8. Type 2:
if + Simple Past, would + infinitive
 An action could happen if the present situation were
different.
 We don’t really expect the situation to change – we
just imagine ‘what would happen if…’
 It is unlikely that I will find the time to go to the show.

9. Type 3: if + Past Perfect
 Type 3 expresses something that is
impossible.
 Eg. If I had finished my homework, I would
have gone to the party.
 The main clause can also be at the
beginning of the sentence:
 Eg. I would have gone to the party if I had
finished my homework.

10. Type 3: if + Past Perfect
 Type 3 conditional sentences refer to situations in
the past.
 An action could have happened in the past if a
certain condition had been fulfilled.
 We just imagine what would have happened if the
condition had been met.
 I wanted to go to the party but I wasn’t able to go to
the party because I hadn’t finished my homework.

11. Type “0”
 The “0” conditional is formed with both clauses in the
present tense.
 It is used to express a certainty, a universal
statement, a law of science, etc.
 Eg. If you heat water to 100 degrees celsius, it boils.
If you don’t eat for a long time, you become hungry.
If the sea is stormy, the waves are high.
 The “0” conditional is different from true conditionals
because the introductory ‘if’ can be replaced by
‘when’ or ‘whenever’.