Add more Challenges

master.tex

@@ -340,6 +340,7 @@ Department for Computer-Networks and Communication-Systems}
 		\item [1] Twitter complete reconstruction of conversation within 30 days
 		\item [2] Are Root-Tweets possibly enough?
 		\item [3] Candidate selection for annotation
+		\item [4] Do argumentive phrases analysed in research differ on Twitter?
 	\end{itemize}
 \end{frame}