同位词从句(apposition clause)同位语从句就是在句子中担当同位语的主谓结构。1.主句中有些词义比较抽象的名词,如:belief, doubt, evidence证据, idea, fact, hope, news, possibility, question, thought等,可以用that、连接代词和连接副词引出同位语从句。There is no doubt that a large number of people benefit from heart surgery.毫无疑问,有许多人得益于心脏外科手术。I have an idea that parents should monitor the kind of television their children watch. 我有一个想法,父母应该检查孩子看电视的内容。There is the news that some British customers will visit our company.  有消息说几个英国客户要来我公司参观。Is there any proof that the food of the plant differs from that of animals? 是否有任何证据可以说明植物性的食物不同于动物性的食物呢?We all know the fact that organization helps memorization. 我们都知道这样一个事实:把要记忆的材料组织起来有助于记忆。注意:虽然that在同位语从句中没有什么意义,但不能省略。区别:尽管由that引导的同位语从句与that引导的定语从句很相似,但两者有明显的区别。 (a)    that在同位语从句中是连词,只起连接作用,无具体词义,不能在从句中充当成分;而用that引导的定语从句中,that是关系代词,在从句中充当一定成分,并有词意。 (b)    同位语从句与其先行词在逻辑上有“主系表”的关系,例如上面的第一句可以理解为:“许多人得益于心脏外科手术是毫无疑问的”上述其它各句也是如此,而定语从句则没有这种关系。