What do DateTime? and using(var x = new y()) mean?
<p>I don't understand what the following lines mean, please explain them to me.</p>

<p>1.</p>

<pre><code>DateTime? pInsertDate;
</code></pre>

<p>At this variable declaration, What does <code>?</code> mean?</p>

<p>2.</p>

<pre><code>using (TransactionScope scope = new TransactionScope())
</code></pre>

<p>At this object creation, What does <code>using</code> mean?</p>
