diff --git a/talk/objectorientation/advancedoo.tex b/talk/objectorientation/advancedoo.tex
index 420fcd59..52a4440b 100644
--- a/talk/objectorientation/advancedoo.tex
+++ b/talk/objectorientation/advancedoo.tex
@@ -245,7 +245,7 @@
   \begin{block}{Principle}
     \begin{itemize}
     \item when overriding a virtual method, the \cppinline|override| keyword should be used
-    \item the \cppinline|virtual| keyword is then optional
+    \item the \cppinline|virtual| keyword is then optional in derived classes
     \end{itemize}
   \end{block}
   \begin{exampleblock}{Practically}
@@ -275,7 +275,7 @@
   \end{block}
   \begin{itemize}
   \item with \cppinline|override|, you would get a compiler error
-  \item if you forget \cppinline|override| when you should have it, you get a compiler warning
+  \item if you forget \cppinline|override| when you should have it, you may get a compiler warning
   \end{itemize}
 \end{frame}