语境预设(contextual presupposition),文学-语言文字-语义学-预设,语用预设的同义术语,可以由词汇和结构造成。徐烈炯在《语义学》中列举了几种语境预设的情形,比如:“It was John who caught the thief.”(是约翰抓住了小偷)预设“Someone caught the thief.”(有人抓住了小偷)是由断裂句(cleft-sentence)结构引起的;“John left before Mary called.”(玛丽打电话来以前约翰就离开了)预设“Mary called.”(玛丽打了电话)是由时间状语从句引起的;“Fred called again.”(弗雷德又打电话来了)预设“Fred had called at least once.”(弗雷德至少打过一次电话)是由“again”表示的重复引起的;“Everyone but Fred left.”(除了弗雷德以外人人都离开了)预设“Fred did not leave”(弗雷德没有离开)与全称量词有关。