Multiline string with added text from variables
<p>I am aware this will work:</p>

<pre><code>string multiline_text = @"this is a multiline text
this is line 1
this is line 2
this is line 3";
</code></pre>

<p>How can I make the following work:</p>

<pre><code>string a1 = " line number one";
string a2 = " line number two";
string a3 = " line number three";

string multiline_text = @"this is a multiline text
this is " + a1 + " 
this is " + a2 + " 
this is " + a3 + ";
</code></pre>

<p>Is it possible without splitting the string into several substring, one for each line?</p>
