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?'
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'dcontact
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.'
