Conditional sentences are sentences which express hypothetical situations and their consequences. They have two parts: the main clause and the dependant or if-clause. They are called conditional because the validity of what is said in the main clause is conditional on (depends on) certain circumstances expressed in the if-clause. For example, If there is a shortage of the product (a hypothetical circumstance or condition), the prices will go up (probable result). The order of the main and if-clause can also be reversed. If the main clause comes before the if-clause, the two clauses are not separated by a comma: The prices will go up if there is a shortage of the product.
There are three kinds of conditional sentences: zero, first, second and third. Each kind contains a different pair of tenses. Certain variations are possible with each type, however if your command of English is not very good, it is better to use the basic forms that you will find below.
