例子：
\documentclass[letterpaper]{letter}
\signature{Assistant director of the intergalactic unit}
\usepackage{tikz}
\begin{document}
\address{Gallifrey, Binary Start System}
\begin{letter}{My Neighbourhood \\ Me \\ EE.UU \\ Planet Earth, Solar System}
\opening{Dear sirs,}
This is a remainder for paying your intergallactic taxes, %etc...
\begin{tikzpicture}
%Beginning of the time line.
\draw[-] (0,0) -- (8.5,0);
\draw (7.5,-.1) node[below,align=center] {overdue compound interest \\ (+15 \%, september 2020)} -- (7.5,.1) node[above] {115 \%};
.
.
.
%etc...
%End of the time line
\end{tikzpicture}
\closing{Sincererly, The Gallifreyan Income Tax Department}
\end{letter}
\end{document}
要添加断线，我们需要align：
\draw (7.5,-.1) node[below,align=center] {overdue compound interest \\ (+15 \%, september 2020)} -- (7.5,.1) node[above] {115 \%};
否则，不会解析任何断线：
\draw (7.5,-.1) node[below] {overdue compound interest \\ (+15 \%, september 2020)} -- (7.5,.1) node[above] {115 \%};
为什么没有默认的文本对齐？