考试类别中的零件环境无法正常显示

Question

在下面的 NQMWE（不是最小的工作示例）中，一个问题有两个parts：

\documentclass[addpoints]{exam}

\pointsinrightmargin

\begin{document}

\header{English 245}{Quiz on \emph{Childhood's End}, pp. 1--23}{2019/02/26}

\vspace{2mm}

\noindent Name: \makebox[0.5\textwidth]{\dotfill}

\vspace{5mm}

\noindent Score: \makebox[1in]{\dotfill} of a possible \numpoints ~points

\begin{questions}
\question The Overlords make two demonstrations of their powers. What are they?
    \begin{parts}
        \part [1]
            \begin{solution}[1in]
            They destroy an incoming missile
            \end{solution}
        \part [1]
            \begin{solution}[1in]
            They block out the sun over Cape Town.
            \end{solution}
    \end{parts}

\question [1] The Overlords communicate through which medium?
\begin{choices}
\choice Written messages
\correctchoice Speech
\choice Video
\choice Musical tones
\end{choices}
\question [1] The Overlords' human liaison works for which organization?
\begin{choices}
\correctchoice The United Nations
\choice The World Health Organization
\choice The US government
\choice The Soviet government
\end{choices}
\question [1] The human opposition to the Overlords focuses on which of the following?
\begin{choices}
\choice \label{choice:cruelty} The cruelty of their rule
\choice \label{choice:concealment}The fact that they choose not to reveal themselves to their subjects
\choice \label{choice:sovereignty}The loss of human sovereignty
\correctchoice \ref{choice:concealment} and ~\ref{choice:sovereignty}, but not ~\ref{choice:cruelty}
\choice \ref{choice:cruelty} and ~\ref{choice:sovereignty}, but not ~\ref{choice:concealment}
\end{choices}
\end{questions}
\end{document}

当我编译它时，parts第一个问题中的没有出现，但其他一切都正常工作（见下图）。（这就是我包含整个文件的原因：除了在环境中，所有选项、标签等都可以正常工作。parts）

这里有什么问题？

Answer 1

您没有提供要\parts [1]打印的附加文本，因此无法打印零件标签。您可以为每个零件添加文本提示（例如，“演示 1”），也可以制作一条零厚度线作为文本提示，以仅显示零件标签。我在您的代码中添加了每个示例。

\documentclass[addpoints]{exam}

\pointsinrightmargin

\begin{document}

\header{English 245}{Quiz on \emph{Childhood's End}, pp. 1--23}{2019/02/26}

\vspace{2mm}

\noindent Name: \makebox[0.5\textwidth]{\dotfill}

\vspace{5mm}

\noindent Score: \makebox[1in]{\dotfill} of a possible \numpoints ~points

\begin{questions}
\question The Overlords make two demonstrations of their powers. What are they?
    \begin{parts}
        \part [1] Demonstration 1: % Use a text prompt
            \begin{solution}[1in]
            They destroy an incoming missile
            \end{solution}
        \part [1] \rule{1em}{0pt}  % Use an 0 thickness line
            \begin{solution}[1in]
            They block out the sun over Cape Town.
            \end{solution}
    \end{parts}

\question [1] The Overlords communicate through which medium?
\begin{choices}
\choice Written messages
\correctchoice Speech
\choice Video
\choice Musical tones
\end{choices}
\question [1] The Overlords' human liaison works for which organization?
\begin{choices}
\correctchoice The United Nations
\choice The World Health Organization
\choice The US government
\choice The Soviet government
\end{choices}
\question [1] The human opposition to the Overlords focuses on which of the following?
\begin{choices}
\choice \label{choice:cruelty} The cruelty of their rule
\choice \label{choice:concealment}The fact that they choose not to reveal themselves to their subjects
\choice \label{choice:sovereignty}The loss of human sovereignty
\correctchoice \ref{choice:concealment} and ~\ref{choice:sovereignty}, but not ~\ref{choice:cruelty}
\choice \ref{choice:cruelty} and ~\ref{choice:sovereignty}, but not ~\ref{choice:concealment}
\end{choices}
\end{questions}
\end{document}

Answer 2

问题出在 ssolution内的环境\part：

\begin{document}

\header{English 245}{Quiz on \emph{Childhood's End}, pp. 1--23}{2019/02/26}

\vspace{2mm}

\noindent Name: \makebox[0.5\textwidth]{\dotfill}

\vspace{5mm}

\noindent Score: \makebox[1in]{\dotfill} of a possible \numpoints ~points

\begin{questions}
\question The Overlords make two demonstrations of their powers. What are they?
    \begin{parts}
        \part [1]
            %\begin{solution}[1in]
            They destroy an incoming missile
            %\end{solution}
        \part [1]
            %\begin{solution}[1in]
            They block out the sun over Cape Town.
            %\end{solution}
    \end{parts}

\question [1] The Overlords communicate through which medium?
\begin{choices}
\choice Written messages
\correctchoice Speech
\choice Video
\choice Musical tones
\end{choices}
\question [1] The Overlords' human liaison works for which organization?
\begin{choices}
\correctchoice The United Nations
\choice The World Health Organization
\choice The US government
\choice The Soviet government
\end{choices}
\question [1] The human opposition to the Overlords focuses on which of the following?
\begin{choices}
\choice \label{choice:cruelty} The cruelty of their rule
\choice \label{choice:concealment}The fact that they choose not to reveal themselves to their subjects
\choice \label{choice:sovereignty}The loss of human sovereignty
\correctchoice \ref{choice:concealment} and ~\ref{choice:sovereignty}, but not ~\ref{choice:cruelty}
\choice \ref{choice:cruelty} and ~\ref{choice:sovereignty}, but not ~\ref{choice:concealment}
\end{choices}
\end{questions}
\end{document}