在某些作表语的形容词后面可以接一个 that 从句,这个that 也可以省略。传统语法把这种从句叫做宾语从句,也有些语法书把这种从句叫做状语从句,还有的语法书把这种从句叫做形容词补足语从句。作为一般的英语学习者,只要知道具体用法即可,不必过于纠结其名称。常见的这种形容词有 afraid, anxious, careful, certain, confident, glad, grieved, hopeful, irritated, pleased, sorry, sure, surprised 等。
在网友的句子“ I am surprised that you should think the exam is pretty diffculty.”中, diffculty应该改为 diffcult,即: I am surprised that you should think the exam is pretty diffcult.在这个句子中, that you should think the exam is pretty diffcult 是宾语从句,同时,这个宾语从句本身也是一个主从复合句:you should think是主句,the exam is pretty diffcult 是宾语从句。