Conditional sentences are sentences expressing
factual implications, or hypothetical situations and their consequences. They
are so called because the validity of the main clause of
the sentence is conditional on
the existence of certain circumstances, which may be expressed in a dependent clause or
may be understood from the context.
A
full conditional sentence (one which expresses the condition as well as its
consequences) therefore contains two clauses: the dependent clause
expressing the condition, called the protasis ; and the main clause
expressing the consequence, called the apodosis.
In English conditional sentences,
the condition clause (protasis) is most commonly introduced by the conjunction if, or sometimes other conjunctions or expressions such as unless, provided (that), providing
(that) and as long
as. Certain condition clauses can also be formulated using inversion without any conjunction (should you fail...; were he
to die...; had they helped us... ; see also the
corresponding section about inversion in the English subjunctive article).
In english language teaching,
conditional sentences are often classified under the headings Zero Conditional,
First Conditional (or conditional I), second conditional (or conditional
II), third conditional (or conditional
III) and mixed conditional,
according to the grammatical pattern followed. A range of variations on these
structures are possible.
a) Zero Conditional
"Zero conditional" refers to conditional sentences
that express a simple implication (see above section), particularly when both
clauses are in the present tense:
If you don't eat for a long time,
you become hungry.
If we burn paper, it becomes ash.
This form of the conditional
expresses the idea that a universally known fact is being described:
If you touch a flame, you burn
yourself.
The act of burning oneself only happens on the condition of
the first clause being completed. However such sentences can be formulated with
a variety of tenses (and moods), as appropriate to the situation.
b) First Conditional
"First conditional" refers to predictive
conditional sentences (see above section); here, normally, the condition is
expressed using the present tense and the consequence using the future:
if + present tense + will + 1st form
of verb
If you make a mistake, someone will let you know.
If I meet him, I will introduce
myself.
If I study hard, I
will pass the final examination.
c) Second Conditional
"Second conditional" refers to the pattern where
the condition clause is in the past tense, and the consequence in conditional
mood (using would or,
in the first person and rarely, should). This is used for hypothetical,
counterfactual situations in a present or future time frame (where the
condition expressed is known to be false or is presented as unlikely).
if + past tense + would + 1st form
of verb
If I liked parties, I would attend more of them.
If it were to rain tomorrow, I would dance in the street.
Rony would buy a new car if he got the job
in foreign company.
If I passed the company entrance test, I
would treat you a plate of steak.
If I were you, I would apply for that
scholarship.
If
it rained tomorrow, I would sleep all day.
The
past tense used in the condition clause is historically the past subjunctive; however in modern English
this is identical to the past indicative except
in certain dialects in the case of the verb be (first and third person singular), where the indicative
is was and the
subjunctive were. In this
case either form may be used (was is
more colloquial, and were more
formal, although the phrase if I
were you is common in colloquial language too):
If I (he, she, it) was/were rich, there would be plenty of
money available for this project.
d) Third Conditional
"Third conditional" is the
pattern where the condition clause is in the past perfect,
and the consequence is expressed using the conditional perfect. This is used to refer to
hypothetical, counterfactual (or believed likely to be counterfactual)
situations in the past.
if + had + would have + 3rd form of verb
If you had called me, I would have come.
If you had remembered to
invite me, I would have attended your party.
If I had had enough
time, I would have come to your wedding party.
If l had worked hard, I
would have got the promotion for manager position.
If I hadn’t gone to the
mountain, I wouldn’t have had an accident.
e)
Mixed
Conditionals
"Mixed conditional" usually refers to a mixture of
the second and third conditionals (the counterfactual patterns). Here either
the condition or the consequence, but not both, has a past time reference:
If you had done your job properly, we wouldn't be in this
mess now.
If we were soldiers, we wouldn't have done it like that.
Source:
