 Since first introduced in 2011, research in DG has undergone a decade progress. Ten years of research in this topic have led to a broad spectrum of methodologies, e.g.,  based on domain alignment, meta-learning, data augmentation, or ensemble learning, just to name a few;
<clarity>  Since first introduced in 2011, research in DG has undergone a decade progress. Ten years of research in this topic have led to a broad spectrum of methodologies, e.g.,  based on domain alignment, meta-learning, data augmentation, or ensemble learning, just to name a few;
 Since first introduced in 2011, research in DG has made great progresses. In particular, intensive research in this topic have led to a broad spectrum of methodologies, e.g., based on domain alignment, meta-learning, data augmentation, or ensemble learning, just to name a few;