Sentence Patterns: Conditional clauses


This page aims to help you with the grammar of conditional clauses.


Conditional sentences are often used in written and spoken academic communication. You will find that they are particularly important in assignments that require you to analyse problems and their solutions. Conditional clauses usually begin with if or unless. The main clause often contains a modal.

  • If you revise thoroughly, you will pass the examination.

  • You use unless to express a negative condition.                        

  • You won't pass the examination unless you revise thoroughly.

1.  Real conditions

You use a 'real' conditional clause when you want to discuss a possible future occurrence. In this sentence, the writer points to the possible consequences of the Shenzhen River filling up with sea water.

  •  If the Shenzhen River fills up with sea water, it will affect the flow of water and could change the habitat of the Mai Po marshes.

 2.  Unreal or hypothetical conditions

 You use an 'unreal' or 'hypothetical' conditional clause when you want to discuss an unlikely situation, e.g. when you want to speculate or wonder 'what if' about a situation or a problem.

  •  If the government increased the basic rate of income tax to 50%, the public would be outraged.

 You can use the pattern if ... were to-infinitive to discuss an imaginary future situation.

  •  If the government were to replace English with Putonghua as the usual medium of tertiary education, it  would probably be very unpopular with students and teachers. 

You will sometimes find it interesting to discuss 'what might have been', i.e. to discuss something that might have happened in the past, but did not actually happen (see Reference Material on Critiquing).

  • If we had checked the equipment carefully, I'm sure the experiment would have been successful.

3.  Necessary conditions

Sometimes you will need to indicate what is necessary for a situation to occur. When you want to indicate a necessary condition, you can use the following conjunctions:

provided (that)    providing (that)   on condition (that)    as long as    only if

  •  You can borrow my laptop provided that you return it by five o'clock.

  •  The universities will probably accept the proposal as long as the government provides sufficient funding.

If you want to point out that one situation would not affect another, you can use even if.


For each of the ten sentences below, choose the best answer from the choices that you are given. If you need help, click on 'Tip'. Check your answers when you have finished.




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Last updated on: Friday, February 01, 2013