如何垂直对齐单元格？

Question

我想垂直和水平对齐表格单元格....有人可以帮忙吗

这是我的代码

\begin{table}[htbp]
  \small
  \centering
  \caption{comparisons}
  \subfloat[Approximation accuracy with the original data]{%
    %\hspace{.5cm}%
        \label{tab:sra}
        \resizebox{\columnwidth}{!}{
    \begin{tabular}{|c|c|c|*{2}{c|}*{2}{c|}}
\hline

Data set & ``?" values&Percent of ambiguity& \multicolumn{2}{|c|}{SR-RSM}& \multicolumn{2}{|c|}{MLST} \\ [3ex]\cline{1-7}
Venture investment&4\%&6\%&80\%&85\%&86\%&85\%\\[3ex]
\cline{3-5}
\hline
Horse&30\%&14\%&81\%&96\%&97\%&96\%\\[3ex]
\hline

Hepatitis&6\%&15\%&53\%&94\%&81\%&94\%\\[3ex]
\hline

\end{tabular}
}
    \hspace{.5cm}%
  }\hspace{1cm}
  \subfloat[Approximation accuracy A]{%
    \label{tab:srb}
    %\hspace{.5cm}%
        \resizebox{\columnwidth}{!}{
    \begin{tabular}{|c|c|c|*{2}{c|}*{2}{c|}}
\hline
Data set & ``?" values&Percent of ambiguity& \multicolumn{2}{|c|}{SR-RSM}& \multicolumn{2}{|c|}{MLST} \\ [3ex]\cline{1-7}
Venture investment&14\%&15\%&37\%&35\%&42\%&36\%\\[3ex]
\hline
Horse&40\%&30\%&61\%&69\%&75\%&80\%\\[3ex]
\hline

Hepatitis&16\%&26\%&33\%&72\%&55\%&83\%\\[3ex]
\hline
\end{tabular}
}
    %\hspace{.5cm}%
  }\hspace{1cm}
  \subfloat[Approximation accuracy B]{%
    \label{tab:src}
    %\hspace{.5cm}%
        \resizebox{\columnwidth}{!}{
    \begin{tabular}{|c|c|c|*{2}{c|}*{2}{c|}}
\hline
Data set & ``?" values&Percent of ambiguity& \multicolumn{2}{|c|}{SR-RSM}& \multicolumn{2}{|c|}{MLST} \\ [3ex]\cline{1-7}
Venture investment&24\%&27\%&37\%&21\%&40\%&36\%\\[3ex]
\hline
Horse&50\%&85\%&58\%&62\%&69\%&73\%\\[3ex]
\hline
Hepatitis&26\%&40\%&27\%&59\%&39\%&66\%\\[3ex]
\hline
\end{tabular}
}
}
\end{table}