2. 1.- Look at this:
IF + PRESENT SIMPLE + PRESENT SIMPLE
If I eat too much, I feel bad.
We use this structure for facts that are generally true:
If I don't get enough sleep, I feel tired.
If you want to become a doctor, you have to study hard.
3. We can say the same thing by reversing the two parts of
the sentence:
PRESENT SIMPLE + IF + PRESENT SIMPLE
I feel bad If I eat too much.
We don't use a comma before IF.
4. 2.- Now look at this:
IF + PRESENT SIMPLE + WILL/ WON'T
If you study, you will pass your exam.
If you don't study, you won't pass your exam.
We use this structure to talk about things that may happen
in the future.
We can reverse the order and again we have to pay
attention to the use of comma.
She'll be angry if I'm late.
If I'm late, she'll be angry.
5. When the if – clause is negative, we can use UNLESS
instead of IF followed by a positive verb:
You won't pass your exam unless you study
pass your exam if you don't study.
= you won't
6. 3.- We don not use will/ won't after IF. We can not say
If I will be late, she'll be angry.*
7. 3.- We don not use will/ won't after IF. We can not say
If I will be late, she'll be angry.*
