Add missing word
diff --git a/Doc/whatsnew/whatsnew25.tex b/Doc/whatsnew/whatsnew25.tex
index 33b7c0c..9affb7f 100644
--- a/Doc/whatsnew/whatsnew25.tex
+++ b/Doc/whatsnew/whatsnew25.tex
@@ -540,7 +540,7 @@
StopIteration
\end{verbatim}
-\keyword{yield} will usually return \constant{None}, you
+\keyword{yield} will usually return \constant{None}, so you
should always check for this case. Don't just use its value in
expressions unless you're sure that the \method{send()} method
will be the only method used to resume your generator function.