Conditionals

A conditional clause states a condition for a result to happen or not happen. In the sentence If it rains tomorrow, we will not go to the beach, the condition is the weather. The result is going or not going to the beach. A conditional clause can come before or after an independent clause.

Conditional Subordinators
if	If you study, you will get good grades. The major would have lost the election if the labor unions had not supported him.
unless	Unless you study, you will not get good grades. The mayor cannot govern unless the labor unions support him.

There are four basic patterns of conditional sentences. Each pattern has a different combination of verb forms depending on whether the time is present, future, or past, and on whether the condition is true or not true. The following chart summarizes the four patterns.

Pattern	Verb form in the if clause	Verb form in the independent clause
1. Present time, true condition	present: If (when) you have a college education,	present: you earn more money.
2. Future time, true condition	present: If you get at least 90% on the final exam,	future: you will get an A in the course.
3. Present or future time, untrue condition	simple past: If Paul were not so lazy,	would + base form: he would get better grades.
4. Past time, untrue condition	past perfect: If the test had been easier,	would have + past participle: all of us would have gotten A's.