Which of the following words is an example of free morphemes?

Which of the following words is an example of free morphemes?
A、Tried．
B、Feet.
C、Worker.
D、Anger.
【正确答案】：D
【题目解析】：本题考查第三章词素中自由词素的相关概念，由于自由词素自由一个自由词根，符合提议的只有D 项anger。此例子在课本第三章自由词素中提及过，需要记住。