The document describes the structure and use of conditional sentences in English. It explains that conditional sentences are made up of an if-clause and main clause, and outlines the different tenses used depending on whether the conditional refers to a possible/hypothetical situation (simple past tense) or something that is always true (present tense). Examples are provided to illustrate conditional sentences discussing situations that depend on present circumstances, past events, or hypothetical scenarios.

1. CONDITIONAL

2.  Is formed if
+ present simple + future simple. It is
used when an actual or potential situation is:
If it rains today, I'll stay at home.
 If clause
 Main clause
 If + Present tense
 will / can / may / must + verb
 If it rains today,
 I'll stay at home

3.  If he is busy now, I will come back tomorrow.
 If she doesn't call you, you can call her
 If you work hard, you may become a
millonaire someday.
 If they don't invite you, you must not go.

4.  This conditional refers to a situation which is
always true (universal truths): If
you freezewater, it turns Into ice.
 If clause Main clause
 If + Present tense Present tense
 If you freeze water it turns into ice.

5.  If you freeze water, it turns into ice.
 If I have time, I usually go to the movies.
 If she doesn't know the answer, she keeps
silent.
 If we don't go out on Saturdays, we rent a
video and stay home.

6.  It refers to a hypothetical situation and the
structure is formed by simple if
+ simple past +conditional
 If clause
 Main clause
 If + Past Simple
 would / could / might + verb
 If I won the lottery,
 I would travel around the world.

7.  If I won the lottery, I would travel around the
world.
 If it were not raining, we could go out.
 If they worked for that company, they might
have better salaries.