conditional-constructionsconjunctionsinversionmodal-verbs
I'll be at my uncle's house in case you need to reach me.
I'll be at my uncle's house just in case you need to reach me.
I'll be at my uncle's house should you need to reach me.I'll be at my uncle's house you should need to reach me.
Could you tell me what the difference between these is?
In addition, when can I invert "should" in such a sentence?
UPDATED: I am wondering what is the exact difference between the bold parts?
If anyone calls, tell him I am busy.
If anyone should call, tell him I am busy.
Now what is the difference between this two?
The first one is a normal conditional sentence, while the second one suggests that the event of calling is unlikely.
Notes from Practical English Usage by Michael Swan -
Should anyone call, tell him I am busy.
We can re-write this sentence as the following -
If anyone should call, tell him I am busy.
Note in the previous case Should anyone call...., we don't use calls.
Please visit this link for more information and examples of should used at the beginning of the sentence with if dropped, as you quoted in your question.
N.B Pam Peters in Cambridge Guide to English Usage suggests that the usage of should in conditional sentence is becoming less often. Conditional uses of should with if included in sentence now sound rather lofty, but the inverted should at the beginning of the sentence with no if included in that clause is still a neat way of prefacing a condition.
In the given context, there's no difference. They mean the same.
'just in case' is the idiom used to mean -in the event that (something happens) i.e. in that condition
should is also used as 'if' and thus, this word too talks about the condition -in the event that/if something happens.
should -expresses a condition i.e. just in case!
Best Answer
is ungrammatical. You need an if in there: if you should need to reach me. The if is only omitted if should is inverted with the subject. The inverted construction is a ‘fossil’ from much older usage; today it is fading into disuse, and has a very quaint ring in the US. Once any verb might be used in this construction, but today only should, had and were are used this way.
The rest of your sentences are all ‘relevance’ conditionals: that is, the protasis (‘condition clause’, ‘if clause’) does not express a condition under which the apodosis (‘consequence clause’, ‘then clause’) is true but a condition under which the information in the apodosis is relevant. For the most part they all express the same thing, which may also be expressed with an ordinary if clause:
However, there is another dimension to the versions with (just) in case. In case may express, alternatively or additionally, the reason why you will be at your uncle’s house: you will be remaining at a particular place (rather than going out) so that you can be reached if that becomes necessary. That is the primary meaning of the expression, as in