I have the following XeTeX document. You can also view it on ShareLaTeX. I have a two-column layout, and sometimes there is a column break that leaves a very huge empty space.
\documentclass[twocolumn]{book}
\usepackage[bottom=1in]{geometry}
\usepackage{xeCJK}
\setCJKmainfont{SimSun}
\newcommand{\pinyin}[1] {{\sffamily #1}}
\newcommand{\definition}[1] {\textsl{#1}}
\usepackage{supertabular}
\parindent=0pt
\begin{document}
\chapter{}
This chapter contains 10 characters. If you know all 10 characters from the beginning of this book through the end of this chapter, you can \begin{itemize}\item recognize 1.5\% of the characters in Chinese movie subtitles.\item recognize 2.4\% of the characters in Chinese books.\end{itemize}On average, characters in this group will appear in 62.39\% of Chinese movies.
\section{一\hfill yī -- \definition{one}\quad}
\subsection*{Origin}
A single horizontal stroke, representing the number one.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}一 & \pinyin{yī} & \definition{one; 1; single; a} \\
一一 & \pinyin{yī yī} & \definition{one by one} \\
\end{supertabular}
\section{二\hfill èr -- \definition{two}\quad}
\subsection*{Origin}
Two horizontal strokes, representing the number two.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}二 & \pinyin{èr} & \definition{two; 2} \\
\end{supertabular}
\section{三\hfill sān -- \definition{three}\quad}
\subsection*{Origin}
Three horizontal strokes, representing the number three.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}三 & \pinyin{sān} & \definition{three; 3} \\
\end{supertabular}
\section{四\hfill sì -- \definition{four}\quad}
\subsection*{Origin}
In ancient texts the character 亖 (four horizontal strokes) was used. The origin of the current form is unclear.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}四 & \pinyin{sì} & \definition{four; 4} \\
\end{supertabular}
\end{document}
As you can see, the right column on the first page is almost completely empty except for the subsection heading, and then the content continues on the second page.
Why is this happening and how can I fix this problem?
Note that I'm automatically generating the LaTeX code from a different source, and I'll end up with a few hundred pages, so I'd rather not do anything that requires manual fiddling with page breaks.