下列配穴中，不属于上下配穴的是：（）
A.梁丘、公孙
B.涌泉、百会
C.中脘、丰隆
D.膻中、关元
E.大椎、绝骨
参考答案：A
The professor explained this theory so clearly that this phenomenon was easy enough ________.
A．for us to work out
B．working out
C．for working out
D．to working out
APD的特点是什么？
