If-Clauses with Ordinary Tenses
When we do not want to suggest that a situation is unreal or imaginary, present tenses are used to refer to the present, past tenses to the past and so on.
If you want to learn a musical instrument, you have to practice.
If you didn’t do much mathematics at school, you will find Economics difficult to understand.
If that was Harry, why didn’t she stop and say hello.
Present tense with future meaning
In the if-clause we normally use a present tense to talk about the future
If I have enough time tomorrow, I will come and see you. (NOT if I will have enough time…)
I will give her your love if I see her. (NOT …if I will see her)
If it is fine tomorrow, I am going to paint the windows.
We can use if +will in polite requests; in this case will is not a future auxiliary; it means “are willing to”
If you will come this way, I will take you to the manager’s office
If your mother will fill in this form I will have her luggage taken up to her room
Would can be used to make a request even more polite
If you would come this way I will take you to the manager’s office .
Wait over there, if you would.
Stressed will can also be used after if when it expresses the idea of insistence.
If you will get drunk every night, it is not surprising you feel ill (=if you insist on getting drunk…)