CONDITIONALS: OTHER WAYS TO EXPRESS UNREALITY
PRESENT AND FUTURE REAL CONDITIONALS

I think Conditional expressions are one of the most important components of programming languages because they enable a program to act differently each time it is executed.

This use is similiar to, and can usually be replaced by, a time clause using 'when':
EXAMPLES:

-When I am late, my father takes me to school.
-If I am late, my father takes me to school.
-She doesn't worry if Jack stays out after school.

Conditional 0 is formed by the use of the present simple in the if clause followed by a comma the present simple in the result clause.

If he comes to town, we have dinner.
OR
We have dinner if he comes to town.

Conditional 1

Often called the "real" conditional because it is used for real - or possible - situations.
EXAMPLES:

-If it rains, we will stay at home.
-He will arrive late unless he hurries up.
-Peter will buy a new car, if he gets his raise.

Conditional 2

Often called the "unreal" conditional because it is used for unreal - impossible or improbable - situations. This conditional provides an imaginary result for a given situation.
The verb 'to be', when used in the 2nd conditional, is always conjugated as 'were'.

EXAMPLES:

If he studied more, he would pass the exam.

I would lower taxes if I were the President.
They would buy a new house if they had more money.

Conditional 3

Often referred to as the "past" conditional because it concerns only past situations with hypothetical results. Used to express a hypothetical result to a past given situation.

EXAMPLES:

If he had known that, he would have decided differently.
Jane would have found a new job if she had stayed in Boston.

Conditional 3 is formed by the use of the past perfect in the if clause followed by a comma would have past participle in the result clause. You can also put the result clause first without using a comma between the clauses.

A06, Jose Pozo