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.
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 French 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
- 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.
* He will buy a car even if he doesn't have the money.
whatever or what ever. You can use either whatever or what ever in sentences such as Whatever (or What ever) made her say that? However, you must use the one-word form when whatever is used as an adjective: Take whatever (not what ever) books you need. The same is true of the forms whoever, whenever, wherever, and however.
whatever and commas. When a clause beginning with whatever is the subject of a sentence, do not use a comma: Whatever you do is right. Otherwise, a comma is fine: Whatever you do, don't burn the toast.
never with'that'. When the phrase preceding a restrictive clause is introduced by whichever or whatever, 'that' should not be used in formal writing. It is regarded as incorrect to write whatever book that you want to look at; instead you should write Whatever book you want to look at will be sent to your office or Whichever book costs less (not that costs less) is fine with us.