O RULES 1 We use the first conditional to talk about the results of actions which are likely or possible / unlikely or imaginary. 2 When if + present simple clause is first, there is / isn't a comma between the two clauses. 3 We never / always use will in the if clause. 4 We can/can't use modal verbs (like should or might) instead of will. 5 Unless + affirmative means the same as if + negative / affirmative.​