How to get the contents between two same nodes?

Question

How do I get the contents between two nodes (under the same parent node) as a string...for example, assume there is a xml file as

<xml version="1.0"?>
<main>
    <abc>This is <day>1day> the <day>5day>th <month>Novembermonth> <year>1993year><abc>
    <xyz>It does not matter what <day>10day> it is <day>3day> of <day>19day><xyz>
<main>

How do I get the contents between the first node and the next node under a any given parent  nodes?. i.e. the output should give the results

" the ",  " it is " and " of ".

 I think it's gonna look something similar to

 

var nodes = Doc.DescendantNodes().OfType<XText>().Select(a=>a.Value) 

but I cannot figure exactly how?

Can someone help...?