"Should you come..." instead of "If you come..."

[Maria Levetsova]

Dear teachers,
I just discovered this forum and I intend to use it a lot. My name is Maria, I am Greek, and for a start I would please like somebody to explaine this to me: In which cases must I say, for example, "Should you feel this is too much for you, then you can... ", rather than "If you feel this is too much for you, then...", or "In case you feel...., then..."?
I read most of the previously put questions but didn't find anything about this issue.
Please give me the theory, using grammatical/syntactical terminology, that way I will really understand.

Many thanks.

[Jamie (K)]

"Should you feel this is too much for you, then you can..." and, "If you feel this is too much for you, then you can..." mean exactly the same thing, and it's just personal choice when to use one or the other. Usually the variant beginning with "should" is considered more formal. Pay attention to the sequence of events these two sentences assume:

1. You feel this is too much for you.
2. You can do this next.

"In case you feel this is too much for you, then you can..." means something much different. Here is the sequence of events it assumes:

1. You can do this first as a precaution.
2. Because later you might feel this is too much for you.

"In case" does not mean the same thing as "if" in English, as equivalent terms often do in other European languages. In English, "in case" indicates that someone is taking an early precaution. Look:

"We will buy a large pizza if Tom comes to visit." This means, "Tom might come to visit, and if he does, we will buy a large pizza after he arrives."

"We will buy a large pizza in case Tom comes to visit." This means, "Tom might come to visit, so we will buy a large pizza now, so that we will have enough later if he arrives."

[Maria Levetsova]

Dear Jamie: So, I've been worrying about the wrong issue. Now I understand it all.
Many thanks,
Maria