（回答不分先后）这里的“ that the family had to move”是什么从句?

Anne's sister Margot was very upset that the family had to move。that the family had to move 是宾语从句。英语中某些形容词或过去分词后常宾语语从句,这些词有：sure,glad,pleased,happy,satified,afraid,surprised,其中连接词that无意义,在从句中不充当任何成分,可以省略,可以说：Anne's sister Margot was very upset the family had to move。再例如：I'm not sure what I ought to do。I'm surprised (that) I didn't see all that before。