\begin{figure*}[htbp] \centering \captions...

\begin{figure*}[htbp]
\centering
\captionsetup[subfigure]{
font=small,
labelfont=bf,
justification=centering
}

text
% -------- Row 1: iAdapter full width --------
\begin{subfigure}[t]{0.98\textwidth}
    \centering
    \includegraphics[width=\linewidth]{AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_iAdapter.pdf}
    \caption{iAdapter}
    \label{subfig:social-iadapter}
\end{subfigure}

\vspace{0.6em}

% -------- Row 2: two methods --------
\begin{subfigure}[t]{0.42\textwidth}
    \centering
    \includegraphics[width=\linewidth]{AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_pre_gpt2.pdf}
    \caption{Pre-GPT}
    \label{subfig:social-pre}
\end{subfigure}
\hfill
\begin{subfigure}[t]{0.42\textwidth}
    \centering
    \includegraphics[width=\linewidth]{AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_post_gpt2.pdf}
    \caption{Post-GPT}
    \label{subfig:social-post}
\end{subfigure}

\vspace{0.4em}

% -------- Row 3: two methods --------
\begin{subfigure}[t]{0.42\textwidth}
    \centering
    \includegraphics[width=\linewidth]{AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_seasonal.pdf}
    \caption{Seasonal}
    \label{subfig:social-seasonal}
\end{subfigure}
\hfill
\begin{subfigure}[t]{0.42\textwidth}
    \centering
    \includegraphics[width=\linewidth]{AnonymousSubmission/LaTeX/iAdapter_pred_curves_SocialGood_h48_s2023_VoT_z_pos_trend.pdf}
    \caption{Trend}
    \label{subfig:social-trend}
\end{subfigure}

\caption{
Qualitative comparison of one-step-ahead online predictions on a
representative sequence from the Social Good dataset over online
steps 0--168. The black curve denotes the ground truth, while the
colored curve denotes the prediction produced by
(a) iAdapter, (b) Pre-GPT, (c) Post-GPT,
(d) Seasonal, and (e) Trend.
All methods track the gradual pre-event variation, but exhibit
different responses to the abrupt regime change around step 123
and the subsequent recovery.
}
\label{fig:social-prediction-comparison}

\end{figure*} 排版不够学术，第一个太大，倒置这个图单独占一页不是文字环绕了