答案1
这可能是一个起点:
\documentclass[border=3mm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[xscale=1.2,font=\footnotesize]
\draw (0,0) -- (12,0);
%
\foreach\m/\n in {0/1,3/N,4/N+1,7/2N,8/2N+1,11/3N}
{\node[scale=.7] at (\m,0) {$|$};
\node[below,yshift=-5pt] at (\m,0) {$\n$};}
%
\path
node[above] at (1.5,0) {$B_1$}
node[above] at (5.5,0) {$B_2$}
node[above] at (9.5,0) {$B_3$};
\end{tikzpicture}
\end{document}