There are two main types of conditionals in English: zero conditional and first conditional. The zero conditional describes something that is always true and uses the structure of present tense in both the if-clause and main clause (e.g. "If you don't eat for a long time, you get hungry"). The first conditional describes something that is likely to happen in the future and uses the structure of present tense in the if-clause and future tense in the main clause (e.g. "If you study hard, you will pass the exam"). Both conditionals can have the clauses reversed or take question form.