that引导同位语从句时，同位语从句的先行词多为抽象名词，如fact，news，hope，question，report，idea，rumour等，而此时从句的连词that只起连接作用，对抽象名词进行解释和说明。that 在从句中不作任何成分，但不能省略。如：
Many young people hold the idea that certificates and work experience help a lot in their job hunting.
许多年轻人有这样一个理念，证书和工作经历对他们的求职作用很大。
The news that his heath is failing made us sad.
他健康状况不佳的消息使我们很难过。
The question who should do the work requires consideration.
谁该干这项工作的问题需要考虑。
There is much chance that Bill will recover from his injury in time for the race.
有很大的机会比利的伤势可以恢复并且按时参加比赛
that 引导同位语从句和定语从句的区别
1）从句法角度来看，引导同位语从句的连词that只起连接作用，在从句中不作任何成分，但不可以省略；而引导定语从句的关系代词that除了连接主句和从句之外，在从句中作一定成分，有时可省略。
Along with the letter was his promise that he would visit me this coming Christmas.
随信一起来的是他的承诺，他说会在即将到来的圣诞节来看我。（同位语从句中的that不做任何成分）
The suggestion (that) he made at the meeting was very right.
他在会议上给出的建议是正确的。（此定语从句中的that在从句中作宾语，可以省略）
2）从语义角度来看，同位语从句that引导的从句在句中解释说明前面的名词，而定语从句中that引导的从句则是起到修饰限定先行词的作用。
The news that we are having a holiday tomorrow is not true.
明天放假的消息不实。（that引导的从句说明news的内容）
He lost his money that had been saved for a long time.
他丢了存了很久的钱。（that引导的定语从句，修饰限定先行词money）