Chapter 9-7: Types of Conditional Sentences
Conditionals or "if clauses" can be used for the following reasons:
To describe a result that might happen in the present or future.
To describe a result that could have happened in the past but didn't.
There are four different types of conditionals. They are each made using different verb tenses and used in different situations.
0 - Zero Conditional
1 - First Conditional
2 - Second Conditional
3 - Third Conditional
Conditional sentences are always formed with some basic components. This is true every time, regardless of the type of conditional.
Condition Clause: if/when + subject + verb structure [+ ... ]
Consequence clause: subject + verb structure [+ ... ]
It is possible to change the order of the clauses. When beginning with the if clause, use a comma to connect the second clause. No comma is needed if starting with the consequence clause.
If you feel tired, you should go and have a nap.
You should go and have a nap if you feel tired.
Conditional structures can be used in different ways. They do not always appear in whole sentences with distinct clauses.
The consequence clause can be used in isolation to answer a conditional question, in reference to a condition clause that was mentioned before, or when appearing in a wider conditional context.
The if clause cannot appear in isolation, because "if" and "when" are conjunctions that require another clause.
The verb structures in conditionals need to be adapted depending on the type of conditional. Notice that each clause has a specific purpose and usually has very different verb structures in a conditional sentence.
It is very important to use the correct structure in the correct clause. You will need to identify each clause to choose the correct verb structure.
Notice that the conjunction if/when may appear at the beginning or the middle of the sentence. However, if or whether always starts the condition clause.
The following table summarizes the types of conditional sentences, when they are used, and the form they take: