求向量组
$$
\alpha_1=\left(\begin{array}{c}
1 \\
-1 \\
2 \\
4
\end{array}\right), \alpha_2=\left(\begin{array}{l}
0 \\
3 \\
1 \\
2
\end{array}\right), \alpha_3=\left(\begin{array}{c}
3 \\
0 \\
7 \\
14
\end{array}\right), \alpha_4=\left(\begin{array}{c}
1 \\
-1 \\
2 \\
0
\end{array}\right)
$$
的一个最大无关组，并将其余向量用这一最大无关组表示.