\begin{frame}{Exercises (1)}
  \begin{exampleblock}{}
    Find a grammar $G$ such that
    \begin{talign}
      L(G) = \{a,b\}^*\,\{c\}\,\{b,c\}^*
    \end{talign}
    \pause
    There are many possible solutions!
    \pause\medskip
    
    One possible solution is:
    \begin{talign}
      S &\to XcY \\
      \mpause[1]{X &\to aX \mid bX \mid \lambda} \\
      \mpause{Y &\to bY \mid cY \mid \lambda}
    \end{talign}
  \end{exampleblock}
\end{frame}