区分定语从句和同位语从句 1定语从句修饰先行词，它和先行词是修饰关系；同位语从句说明先行词的具体内容，是补充说明的关系 (1) The plane that has just taken off is for London. 定语从句 (2) The fact that he has been dead is clear. 同位于从句 2. 同位语从句和先行词一般可以用be动词发展成一个完整的句子，而定语从句不可以 (1) The idea that we could ask the teacher for advice is wonderful. (2) The idea was that we could ask the teacher for advice. (3) The fact that the earth moves around the earth is known to all.(4) The fact is that the earth moves around the earth.6