原发性癫痫的病因是（）
A.先天性脑发育异常
B.颅脑外伤
C.全身疾病
D.颅脑肿瘤
E.遗传因素
参考答案：E
His failure in the experiment suggested that he ________ his teacher’s proper instructions.
A．should not have followed
B．should not follow
C．mustn’t have followed
D．hadn’t followed
首位城市分布的优缺点？
