\begin{equation}\label{loss_sen}
\small
    \mathcal{L}_{sen} = -\frac{1}{J}\sum_{j=1}^{J}(\text{log}p(\mathbf{s}_i^j|\mathbf{s}_i^{<j}, \mathcal{V})) + \sum_{\mathbf{s}_i^* \in \mathbf{s}_i}\text{log}(1-p(\mathbf{s}_i^*|\mathbf{s}_i^{<j}, \mathcal{V})),
\end{equation}
