The reason is that 后加一个完整的句子，比如the reason is that there is ont anyone in particular I want to see.这个that从句做表语从句修饰reason并切不可以省略这样理解对么？

Going to the reunion means that I have to.. 后接一个完整的句子，这里这个that从句是否为同位语从句用来解释说明going to the reunion，这样理解对么？同位语从句的话that不可以省略，对么？

谢谢.