Conditional Type 1

Conditional Type 1 is also called the first conditional or future conditional. Both clauses refer to future although the verb in the if clause is in a present tense.

Conditional Type 1 usually expresses aspects of persuasion, such as cajoling and negotiating, and for giving warning and making threats.

Persuasion: I’ll do the cooking if you do the cleaning.
Warning: If you go on like this, you’ll make yourself ill.
If you don’t hurry, you’ll be late.
Threat: If you don’t apologize, I will never speak to you again.
              If you do it again, I’ll call the police.

The basic form of Conditional Type 1
main clause [will+V]
if clause [if+V in present simple]

Other forms:

main clause [can+V]
if clause [if+V in present simple]
used to make an offer or a suggestion, e.g. If you want, we can take the bus.

main clause [imperative]
if clause [if+V in present simple]
used to give advice or instructions, e.g. If you go to the supermarket, bring back a carton of milk please.

main clause [present continuous] or [be going to]
if clause [if+V in present simple]
E.g. We’re staying at home on Wednesday if the transport strike goes ahead. They’re going to take their mother to the old house if she remembers where it is.
Nota bene: present continuous and be going to express future

main clause [will+V]
if clause [if+V in present continuous] or [if+V in present perfect]
E.g. If they’re watching TV, they will not hear you.
       If it hasn’t rained by the weekend, we’ll have to water the garden.

Should in Conditional Type 1:
main clause [will+V]
if clause [if+should+V]
used to weaken the possibility of something happening, implying by any chance. E.g. If you should find yourself at a loose end over the holiday, you’ll always be welcome at our house.

formal written situaitons:
main clause [will+V]
if clause [should+S+V]
Should is sometimes used in place of if, usually in more formal, written contexts. E.g. Should you have any questions, please contact us.
Should people complain about the quality of any goods, please refer them directly to the customer services department.