1\documentclass[11pt]{article}
2\begin{document}
3
4\section{Example for paragraphs}
5
6Some roman text
7
8{\tt
9should be typewriter font
10
11should be typewriter font
12}
13
14\section{Example for itemize}
15
16Another example
17
18\begin{itemize}
19\item one roman
20{\tt
21\item two typewriter
22\item three typewriter
23}
24\begin{itemize}
25\item subitem roman
26\item subitem roman
27\end{itemize}
28\end{itemize}
29
30Now a numbered list
31
32\begin{enumerate}
33\item one roman
34{\tt
35\item two typewriter
36\item three typewriter
37}
38\begin{enumerate}
39\item subitem roman
40\item subitem roman
41\end{enumerate}
42\end{enumerate}
43
44\section{Example for sections}
45But sections are impervious!
46
47\subsection{Title is roman}
48Text is in roman.
49
50{\tt
51\subsection{Two in roman}
52Text is in typewriter.
53
54\subsection{Three in roman}
55Text is in typewriter.
56}
57\end{document}
58