\begin{frame}{Introduction to Grammars}

  \vspace{-1ex}
  \begin{exampleblock}{}
  \vspace{-.5ex}
  \begin{tabular}{rcl}
    $\langle$sentence$\rangle$ & $\to$ & 
    $\langle$article$\rangle$ $\langle$noun$\rangle$ $\langle$verb$\rangle$ $\langle$article$\rangle$ $\langle$noun$\rangle$ \\[-.25ex]
    $\langle$article$\rangle$ & $\to$ & the \\[-.25ex]
    $\langle$article$\rangle$ & $\to$ & a \\[-.25ex]
    $\langle$noun$\rangle$ & $\to$ & farmer \\[-.25ex]
    $\langle$noun$\rangle$ & $\to$ & cow \\[-.25ex]
    $\langle$verb$\rangle$ & $\to$ & milks
  \end{tabular}
  \vspace{-.5ex}
  \end{exampleblock}
  \medskip
  
  \alert{The farmer milks a cow} is a sentence in the language.
  \begin{minipage}{.8\textwidth}
    \vspace{-1ex}
    \begin{talign}
      \mpause[1]{\langle\text{sentence}\rangle} 
      \mpause{&\Rightarrow \langle\text{article}\rangle \langle\text{noun}\rangle \langle\text{verb}\rangle \langle\text{article}\rangle \langle\text{noun}\rangle} \\
      \mpause{&\Rightarrow \text{the }\langle\text{noun}\rangle \langle\text{verb}\rangle \langle\text{article}\rangle \langle\text{noun}\rangle} \\
      \mpause{&\Rightarrow \text{the farmer }\langle\text{verb}\rangle \langle\text{article}\rangle \langle\text{noun}\rangle} \\
      \mpause{&\Rightarrow \text{the farmer milks }\langle\text{article}\rangle \langle\text{noun}\rangle} \\
      \mpause{&\Rightarrow \text{the farmer milks a }\langle\text{noun}\rangle} \\
      \mpause{&\Rightarrow \text{the farmer milks a cow}}
    \end{talign}
  \end{minipage}~%
  \begin{minipage}{.19\textwidth}
  \includegraphics[height=22.5mm]{milk-cow.jpg}
  \end{minipage}
%   \smallskip
%   
%   \mpause{\alert{The cow milks the farmer} is also a sentence in the language.}
\end{frame}