CONDITIONAL
Conditional tenses are used to speculate about what
could happen, what might have happened, and what we wish would happen. In
English, most sentences using the conditional contain the word if. Many
conditional forms in English are used in sentences that include verbs in one of
the past tenses. This usage is referred to as “the unreal past” because
we use a past tense but we are not actually referring to something that
happened in the past. There are five main ways of constructing conditional
sentences in English. In all cases, these sentences are made up of an if clause
and a main clause. In many negative conditional sentences, there is an
equivalent sentence construction using “unless” instead of
"if".
Conditional
sentence type
|
Usage
|
If
clause verb tense
|
Main
clause verb tense
|
Zero
|
General
truths
|
Simple
present
|
Simple
present
|
Type 1
|
A
possible condition and its probable result
|
Simple
present
|
Simple
future
|
Type 2
|
A
hypothetical condition and its probable result
|
Simple
past
|
Present
conditional or
Present
continuous conditional
|
Type 3
|
An
unreal past condition and its probable result in the past
|
Past
perfect
|
Perfect
conditional
|
Mixed
type
|
An
unreal past condition and its probable result in the present
|
Past
perfect
|
Present
contditional
|
THE ZERO CONDITIONAL
The zero conditional is used for when the time being
referred to is now or always and the situation is real and
possible. The zero conditional is often used to refer to general truths. The
tense in both parts of the sentence is the simple present. In zero conditional
sentences, the word "if" can usually be replaced by the word
"when" without changing the meaning.
If
clause
|
Main
clause
|
If +
simple present
|
simple
present
|
If
this thing happens
|
that
thing happens.
|
If you
heat ice
|
it
melts.
|
If it
rains
|
the
grass gets wet.
|
TYPE 1 CONDITIONAL
The type 1 conditional is used to refer to the present
or future where the situation is real. The type 1 conditional refers
to a possible condition and its probable result. In these sentences the if
clause is in the simple present, and the main clause is in the simple future.
If
clause
|
Main
clause
|
If +
simple present
|
simple
future
|
If this
thing happens
|
that
thing will happen.
|
If you
don't hurry
|
you
will miss the train.
|
If it
rains today
|
you
will get wet.
|
TYPE 2 CONDITIONAL
The type 2 conditional
is used to refer to a time that is now or any time, and a situation that
is unreal. These sentences are not based on fact. The type 2 conditional
is used to refer to a hypothetical condition and its probable result. In type 2
conditional sentences, the if clause uses the simple past, and the main clause
uses the present conditional.
If
clause
|
Main
clause
|
If +
simple past
|
present
conditional or present continuous conditional
|
If
this thing happened
|
that
thing would happen. (but I'm not sure this thing will happen) OR
that thing would be happening. |
If you
went to bed earlier
|
you
would not be so tired.
|
If it
rained
|
you
would get wet.
|
If I
spoke Italian
|
I
would be working in Italy.
|
TYPE 3 CONDITIONAL
The
type 3 conditional is used to refer to a time that is in the past, and a
situation that is contrary to reality. The facts they are based on are the
opposite of what is expressed. The type 3 conditional is used to refer to an
unreal past condition and its probable past result. In type 3 conditional
sentences, the if clause uses the past perfect, and the main clause uses the
perfect conditional.
If
clause
|
Main
clause
|
If +
past perfect
|
perfect
conditional or perfect continuous conditional
|
If
this thing had happened
|
that
thing would have happened. (but neither of those things really happened) OR
that thing would have been happening. |
If you
had studied harder
|
you
would have passed the exam.
|
If it
had rained
|
you
would have gotten wet.
|
If I
had accepted that promotion
|
I
would have been working in Milan.
|
MIXED TYPE CONDITIONAL
The mixed type conditional is used to refer to a
time that is in the past, and a situation that is ongoing into the
present. The facts they are based on are the opposite of what is expressed. The
mixed type conditional is used to refer to an unreal past condition and its
probable result in the present. In mixed type conditional sentences, the if
clause uses the past perfect, and the main clause uses the present conditional.
If
clause
|
Main
clause
|
If +
past perfect or simple past
|
present
conditional or perfect conditional
|
If
this thing had happened
|
that
thing would happen. (but this thing didn't happen so that thing isn't
happening)
|
If I
had worked harder at school
|
I
would have a better job now.
|
If we
had looked at the map
|
we
wouldn't be lost.
|
If you
weren't afraid of spiders
|
you
would have picked it up and put it outside.
|
source: http://www.edufind.com/english-grammar/conditional/
