下列药物中既能平肝潜阳，又能熄风止痉的是()
A．羚羊角
B．石决明
C．天麻
D．钩藤
E．磁石
参考答案：A,C,D
“战国七雄”不包括( )。
A．秦
B．晋
C．燕
D．楚
We didn't start our discussion _____ everybody arrived. [ ]
A. since
B. if
C. while
D. until
