Grammar : if and unless

Grammar: IF and Unless Clauses

1. IF CLAUSES

In English we distinguish three (3) types of If Clauses:

A- TYPE ONE 

        Rule

IF + Simple present + Simple future

Example: If you go to Washington, you will see the White house.

Use:

 It is used to express an action which will take place in the future, conditioned by a present one.

Example: If my father comes back early from work, we shall all go to the cinema.

B- TYPE TWO:

Rule

IF + Simple past + Conditional simple

Example: If you went to Washington you would see the White house.

Use:

It is used to express an action which would or could not take place basing on  a non set past condition.

Example: If he arrived at church on time the priest would bless him before travelling.

We also used this type to express an unreal past.

Example:

-If Mr Dickson were a tantalizing lady, he would have so many suitors.

- Were I a singing bird, I would wake people up everyday early in the morning by means of my sweet songs.

C- TYPE THREE

Rule

IF + past perfect + conditional perfect

Example:

Had I known, I would have never stolen the poor.

Use

It is used to express a past regret.

Example: If I had taken part in the International quiz competition, I would have won the first prize in order to get a scholarship for Cambridge University.

D- OTHER FORMS:

Hadn’t it been for + Noun + Conditional perfect

Example: Hadn’t been for my failure last year, I would have been in London this year for my studies

Hadn’t it been for the fact that our grand father had died early, we would have got the chance to get English nationality.

Hadn’t it been for the earlier death of our grand father, we would have got the chance to own the English nationality.

II- THE SYSTEMATIC USE OF UNLESS:

Rules

1. IF+ Aff +Aff

Unless + Aff + Negation

Example: If I go to the USA, I shall see the White House

If I don’t go to the USA, I shan’t see the White House

Unless I go to the USA, I shan’t see the White House

1. IF+ Aff + Neg = Unless + Aff + Aff  (and vice versa).

Example: If we don’t learn hard, we will fail our final exam.

We will fail our final exam unless we learn hard.

Example: If it rains, we shall not go out.

Unless it rains, we shall go out.

1. IF + Neg + Neg = Unless + Aff + Neg

Example: If I don’t sleep now I will not rest enough.

Unless I sleep now, I will not rest enough.

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