新列表环境

Question

我需要一个新的列表环境，详细信息在上图中给出。

Answer 1

像这样吗？

\documentclass[11pt]{report}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fourier}
\usepackage[showframe]{geometry}
\usepackage{enumitem}
\usepackage{fancyvrb}
\parindent=0pt
\begin{document}

First of all I am lost in listing environments: itemize, description, enumerate…

I am tired to change the preamble by trial and error.

What I need is a list like this:
\begin{enumerate}[ leftmargin=*, noitemsep, widest=000, topsep=1.4ex]
  \item First item

  \item Second Second. Second Second Second…

        Second item. \setcounter{enumi}{106}

  \item Another item.
\end{enumerate}
The starting point of the items is left margin.

The spacing before the first item and after the last item are intended to be \verb|\onehalfspacing|.

But the spacing between the items should be \verb|\singlespacing|.

By the way the document class is report.

\end{document}