fix wrong english.

methane · methane · commit d2b42ed4e354 · 2012-09-07T18:13:18.000+09:00
diff --git a/tutorial.md b/tutorial.md
@@ -452,7 +452,7 @@ except Timeout:
 </code>
 </pre>
 
-Or with a context manager in a ``with`` a statement.
+Or with a context manager in a ``with`` statement.
 
 <pre>
 <code class="python">import gevent
