\documentclass[12pt,twoside,a4paper]{article}
\usepackage{times,parskip}
\usepackage{enumerate,graphicx}
\usepackage{amsmath,amssymb}
\usepackage{alltt}
\usepackage{bm}

\usepackage{mscexam}
\usepackage{msc99}
\pagestyle{exam}
\newcommand{\papernumber}{JAST}
\newcommand{\examcode}{JAST}
\renewcommand{\ttdefault}{cmtt}
\newcommand{\bmid}{\,|\,}
\let\hat=\widehat
\newcommand{\bit}{\begin{itemize}}
\newcommand{\eit}{\end{itemize}}
\newcommand{\U}{ {\cal U}([0,1])}
\newcommand{\beas}{\begin{eqnarray*}}
\newcommand{\enas}{\end{eqnarray*}}
\newcommand{\bea}{\begin{eqnarray}}
\newcommand{\ena}{\end{eqnarray}}
\newcommand{\e}{{\bf E}}
\newcommand{\p}{{\bf P}}
\newcommand{\corr}{\mbox{corr}}
\newcommand{\prob}{\mbox{pr}}
%\newcommand{\mod}{\mbox{mod}}
\newcommand{\eps}{\varepsilon}
\let\leq=\leqslant
\let\geq=\geqslant
\begin{document}

\question

Write the body of your question here and enumerate the parts as
indicated below:

\begin{enumerate}[(a)]
\item First part

\item Second part. This question has subparts, which should be
enumerated as below.


\begin{enumerate}[(i)]
\item First subpart

\item Second subpart

\item Third subpart
\end{enumerate}

\end{enumerate}

\question

Here comes another question...

\begin{enumerate}[(a)]
\item First part

\item Second part. This question has subparts, which should be
enumerated as below.


\begin{enumerate}[(i)]
\item First subpart

\item Second subpart

\item Third subpart
\end{enumerate}

\end{enumerate}

\end{document}
