以下不属于感应电的治疗作用的是（）。
A.防治肌萎缩
B.防止黏连
C.止痛
D.促进神经再生
E.促进肢体血液和淋巴循环
参考答案：D
The first few years in the 21st century ______ the rapid rise of China as a world economic power.
A．witness
B．has witnessed
C．will witness
D．have witnessed
人口发展面临的挑战有哪些？
