患者，男性，25岁。早晨起床时发现四肢乏力，双下肢明显，持续1天后症状消失，发病前有饮酒史，既往曾发作2次。每次发作腰穿查脑脊液常规、生化无异常发现。体检：四肢肌力Ⅲ级，肌张力降低，腱反射减低，感觉正常。
此病的发病机制目前认为和下列哪项有关（）
A.肌纤维炎性坏死
B.神经肌肉接头的乙酰胆碱受体减少
C.肌纤维内肌浆网的离子通道异常
D.中枢神经系统脱髓鞘
E.肌纤维内线粒体功能异常
参考答案：C
Passage Three
In the author’s opinion, ______.
A．learning plays an important part in most aspects of a child’s development and change
B．there are hardly any principles of learning which are generally accepted
C．a child never learns anything unless he has some need or desire for it
D．a child should not be rewarded until he has learned a response
