Conditionals and clauses
Zero and first conditional and time/condition clauses
A conditional sentence has two parts: an 'if-clause' (the condition) and a main clause (the result). We use the zero conditional to talk about general truths and scientific facts; both verbs are in the present simple, and 'if' often means 'when' (If you heat water to 100 degrees, it boils). We use the first conditional to talk about real or likely situations in the future; the if-clause uses the present simple and the main clause uses 'will' or 'won't' plus the base verb (If it rains, I will stay home). A very important rule is that we do not use 'will' in the if-clause or in a time clause, even though the meaning is future (NOT 'If it will rain'). The word 'unless' means 'if not', so 'I won't go unless you come' means 'I won't go if you don't come'. We follow the same rule with time clauses introduced by when, while, before, after, as soon as and until: the verb after these words stays in the present simple to talk about the future. For example: 'I will call you as soon as I arrive', not 'as soon as I will arrive'.
Rules
- 1Zero conditional (general truths/facts): If/When + present simple, present simple — If you mix blue and yellow, you get green.
- 2First conditional (real/likely future): If + present simple, will/won't + base verb — If she studies, she will pass.
- 3Never use 'will' in the if-clause or a time clause: say 'If it rains' (NOT 'If it will rain').
- 4'unless' = 'if not': I won't go out unless the rain stops (= if the rain does not stop).
- 5After time words (when, while, before, after, as soon as, until) use the present simple for the future: I will text you when I get there (NOT 'when I will get there').
Practice
10 easy · 10 medium · 10 hard