在标题页上的日期和摘要之间添加文本的适当间距？

Question

如下面代码所示，我想在日期和摘要标题之间添加两行，同时保持适当的间距，以便标题移到顶部。现在，如果我的摘要足够长，间距就会挤到底部。

\documentclass[12pt,letterpaper,fleqn]{article}       

\onehalfspacing

\begin{document}

\begin{titlepage}

\title{How to add texts in between date and abstract to get proper spacing in title page?\thanks{Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.}}

\author{Adam Smith}
\medskip
\date{October 6, 2018}}
\maketitle

%%% How to add these two lines here to get proper spacing in title page?
\begin{center}{This is the first line}\end{center}
\begin{center}{This is the second line}\end{center}


%%%   ABSTRACT
\begin{abstract}
\noindent
This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.

\bigskip
\end{abstract}
\setcounter{page}{0}
\thispagestyle{empty}
\end{titlepage}

\end{document}

标题、名称、日期是否可以向上移动，以便下面的其他内容有适当的空间？

Answer 1

刚刚从这个线程中获得启发，在适当的位置使用 vspace：将标题和作者文本上移？

\documentclass[12pt,letterpaper,fleqn]{article}       

\onehalfspacing

\begin{document}

\begin{titlepage}

% spacing option
\title{\vspace{-1.0cm}How to add texts in between date and abstract to get proper spacing in title page?\thanks{Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.Thank StackExchange.}}

\author{Adam Smith}
\medskip
\date{October 6, 2018}}
\maketitle

%%% How to add these two lines here to get proper spacing in title page?
\begin{center}
\vspace{-1.0cm}       % spacing option
This is the first line \\
This is the second line
\vspace{0.5cm}        % spacing option
\end{center}


%%%   ABSTRACT
\begin{abstract}
\noindent
This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.This an abstract.

\bigskip
\end{abstract}
\setcounter{page}{0}
\thispagestyle{empty}
\end{titlepage}

\end{document}