Using the conditional - www.geilien.cn


	Using the conditional


				Oleg from the Ukraine asks: Could you please tell me the rule for using should in questions like this: 'Should you have any problems, feel free to contact me.' What does it mean? And how does it differ from: 'If you have any questions, please contact me?'


	Roger replies:


			These two sentences are very similar in meaning. But 'Should you have...' or 'If you should have...' may be used in preference to 'If you have...' if we want to suggest a slight possibility of something happening or when we are making suggestions or giving advice. Compare: 'If you have any free time, make sure you visit the old town.' (It's possible, or even likely, that you may have some free time.) 'If you should have any free time, make sure you visit the old town.' (I don't really expect you will have any free time, but if you do...) 'Should you fail this exam, you can always re-take it next year.' (I think it's unlikely, but it's possible you may fail it and if you do...) 'If you fail this exam, you can always re-take it next year.' (I'm just pointing this out to you. I don't have a strong opinion on the matter one way or the other.)

Note that for a condition that is generally true, as in all the examples above, we use if plus the present simple in the subordinate clause and the present simple again in the main clause:

If + PRESENT SIMPLE , PRESENT SIMPLE

Look at these examples:

'I get indigestion, if I eat too quickly.'

'If I go on a diet and lose some weight, I invariably put it back on again afterwards.'

'If she stays up late, she always oversleeps the next day.'

'If you're not sure about the meaning, use your dictionary to look up any unknown words.'

With this type of condition, we could often use whenever or when instead of if.

This is distinct from the will condition when we are predicting a likely result in the future and thinking about specific instances. With this type of condition, we have if plus the present simple in the subordinate clause and will/won't, or sometimes going to, in the main clause:

If + PRESENT SIMPLE, will/won't/going to FUTURE REFERENCE

Look at these examples:'

If we hurry, we'll get the 12 o' clock train.'
'It's quite simple. If he takes the antibiotics, he'll get better. If he doesn't, he won't.'
'If they win the lottery, they're going to donate all the money to good causes. That much is already decided.'

Note also that except for the above usage of should, we do not normally use would or should (or shall or will, see above) with if in the subordinate clause. For the would condition, when we are talking about something unreal or unlikely in the present or future, we normally use if plus the past simple in subordinate clause and would / should / 'd in the main clause:

If + PAST SIMPLE , would / should/ 'd PRESENT/FUTURE

Look at these examples:

'Even if he offered me a million pounds, I should still refuse to work for him.'

'If we stopped advertising our products, nobody would buy them.'

'If I had longer holidays in the winter, I'd go to places like South Africa or South America.'

'If I knew how to reach her, I'd contact her straightaway.'

However, there is one exception to this general rule. If we are talking about willingness to do something, then it is possible to use would, as an alternative to the past simple, in the if clause:

'If you would only tell me what the problem was, I would help you to find a solution.'
'If you would help me with the painting, we would finish decorating this room today.'


			(For further uses of should and would, see 'When to use will, shall, would, should')