Page 127 - New Grammar with a Smile 8

In sentence 1, the if-clause, If Joe stays up late, is in the simple present, and the
main clause, he can finish his assignment, is also in the simple present with a modal
auxiliary ‘can’ before the infinitive ‘finish’. The conclusion in the main clause doesn’t
automatically follow from the condition in the if-clause, yet, it is quite possible.

In sentence 2, the if-clause, If Joe stayed up late, is in the simple past, while the
main clause, he could finish his assignment, uses modal ‘could’ + infinitive ‘finish’.
It conveys that the reporter does not really believe that the condition in the if-clause
would be fulfilled.

In sentence 3, the if-clause, If Joe had stayed up late, is in the past perfect, while
the main clause, he would have finished his assignment, is in the future perfect
in the past. The conclusion in the main clause didn’t hold—Joe certainly didn’t finish
his assignment. From this, we conclude that the condition in the if-clause wasn’t
fulfilled, i.e., Joe didn’t stay up late.

1. Zero Conditionals

A conditional sentence which expresses a scientific or generally accepted fact is
called a zero conditional. In this type of conditional, the content of the main
clause automatically follows from the condition in the if-clause with one hundred
per cent certainty.

If we apply the explanation given above to this sentence:
• If an apple drops from a height, it will fall to the ground.

It will definitely fall to the ground. There can be no other conclusion.

The if-clause in a zero conditional sentence is generally in the simple present,
while the main clause is, either the simple present or the simple future. The
basic form is:

If + clause in the simple present + clause in the simple present/simple future,

For example,
• If it rains right now, it will ruin the crops.

2. Conditionals of Type 1 (Time: Present or Future)

These are conditionals which indicate a result which could hold with a reasonable
probability, assuming that the condition in the if-clause will be fulfilled. Since
there is a possibility that the action of the if-clause will be done, such conditionals
are also called likely conditionals.

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