脱疽早期的主要表现是( )
A．肢体水肿B．肤温升高C．臁疮D．肤温降低E．肤色紫暗
参考答案：D
What are they doing? [ ]
A. She is singing.
B. He is crying.
C. They are talking.
试述微笑的功能。
