Enumerate Package

Question

I'm trying to write an exam paper using LaTeX. I use the enumerate package, e.g.

\begin{enumerate}
  \item This question is about balloons.
    \begin{enumerate}
      \item What shape are balloons?
      \item What colour are balloons?
    \end{enumerate}
\end{enumerate}

The problem comes from when I want to put commentary into the question. At the moment, the first level of enumerate gives me a number, and the second a letter. But in between the letters, I might like to say something about the next part of the question, and I would like that outdented, i.e. not on the same level as the lettered parts of the question. I have a work around:

\begin{enumerate}
  \item This question is about balloons.
    \begin{enumerate}[(a)]
      \item What shape are balloons?
    \end{enumerate}
  Assume that all balloons are the same shape.
    \begin{enumerate}[(b)]
      \item What colour are balloons?
    \end{enumerate}
\end{enumerate}

This is a real pain in the you-know-what. Doing it this way, everything in the last enumerate environment gets labelled as (b). So I have to \begin{enumerate} and \end{enumerate} and label every subsequent part:

\begin{enumerate}
  \item This question is about balloons.
    \begin{enumerate}[(a)]
      \item What shape are balloons?
    \end{enumerate}
  Assume that all balloons are the same shape.
    \begin{enumerate}[(b)]
      \item What colour are balloons?
    \end{enumerate}
    \begin{enumerate}[(c)]
      \item Why do I have to keep doing this?
    \end{enumerate}
    \begin{enumerate}[(d)]
      \item Why do I have to keep doing this?
    \end{enumerate}
\end{enumerate}

Answer 1

This is quite easy with enumitem:

\documentclass{article}
\usepackage{enumitem}
\newlist{subquestion}{enumerate}{1}
\setlist[subquestion,1]{label=(\alph*)}

\begin{document}
\begin{enumerate}
\item This question is about balloons.
   \begin{subquestion}
   \item What shape are balloons?
   \end{subquestion}
Assume that all balloons are the same shape.
  \begin{subquestion}[resume]
  \item What colour are balloons?
  \item Why do I have to keep doing this?
  \end{subquestion}
Something else.
  \begin{subquestion}[resume]
  \item Why do I have to keep doing this?
  \end{subquestion}
\end{enumerate}
\end{document}