What Will Happen?
Zero Conditional
Use the zero conditional if an action always occurs as the result of another action. The zero conditional is used to express conditions that are always true.
Example:
"If I eat fried foods, my stomach gets upset."
Tom sneezes if he works with spices.
The present simple is used in both the 'if' clause and the result clause.
'If' clause - present simple + , + result clause - present simple
"If I eat fried foods, my stomach gets upset."
Tom sneezes if he works with spices.
Do not use a comma, when placing the result clause first.
Tom sneezes if he works with spices.
First Conditional
Use the first, or 'real', conditional if an action will occur if something happens. The first conditional is used when a result is realistically possible.
'If' clause - present simple + , + result clause - future with will
What will they do if the decoration is ugly?
How will we provide a casual dining experience if we don't install a buffet?
Do not use a comma, when placing the result clause first.
She will offer various types of lodging if the customers don't state their specific needs.
'Unless' is also used in the first conditional to mean 'if not'.
If he doesn't come soon, we won't go to lunch = Unless he comes, we won't go to lunch.
Use of 'May' and 'Might' in the First Conditional
When a future result is not certain based on a condition, use 'may' or 'might'.
'If' clause - present simple + , + result clause - 'may / might' + verb
Ecotourism might make up for the loss in profits if the advertising campaign is successful.
Security will tighten if there is another terrorist attack.