百日咳痉咳期的治法是( )
A．清热肃肺B．泻肺镇咳C．宣肺止咳D．清肺化痰E．滋阴润肺
参考答案：B
Apartments in cities can be quite high. Renters are paying up to $1,000 per month for _______ bedroom apartment.
A．one a
B．the one
C．one
D．a one
如果石油价格上涨50%，引起需求量降低了10%，则石油的价格弹性为( )
A．-5 B．-0.5C．-0.2 D．不能确定
