炮制后毒性降低的是（）
A.醋甘遂
B.醋柴胡
C.盐黄柏
D.酒川芎
E.盐杜仲
参考答案：A
Our math teacher is very kind ______ he looks very serious.
A．because
B．though
C．if
D．when
椎基底动脉系统短暂脑缺血发作，不出现的症状是
A．失写
B．眩晕
C．构音障碍
D．复视
E．交叉瘫
