— How much _____ the socks?
— Three dollars. [ ]
A. is
B. are
C. do
D. does
答案:B
下列哪个镇静催眠药能明显缩短快波动眼睡眠期()
A.水合氯醛
B.地西泮
C.苯巴比妥
D.氯丙嗪
E.苯海拉明