existential construction 基本例句 存现句 In existential sentences, location and time phrase before MV or BV verb can be viewed as the subject, no matter whether it has semantic choice relation with the verb.存现句中,不论是一价动词前还是二价动词前的处所和时间词语,也不论其与动词是否具有语义上的选择关系,都可以看成主题。