Sluicing refers to a certain type of compound sentence in which one clause is a wh question where all sentential elements, but the wh-phrase itself alone, are omitted. In semantic interpretation, a sluicing sentence is comparable to a full wh interrogative. The study of sluicing sentence involves several important aspects of syntactic theory. Zhang and Xu in their article provide a unified account of sluicing in Chinese and English from the perspective of predicative Empty Category [1]. It is demonstrated in this article that one important issue still remains to be resolved regarding the similarities and differences between Chinese and English in sluicing: What remains after deletion in English is the wh-phrase alone, but there must be a copular verb going with the retained wh-phrase in Chinese. As the major new viewpoint articulated in this article, the above cross-linguistic contrast is illustrated to be more principally explainable by appealing to the theory of focus rather than by using ad hoc stipulations.