胸骨左缘第2肋间有连续性震颤，提示
A．主动脉瓣狭窄
B．主动脉瓣关闭不全
C．肺动脉瓣狭窄
D．动脉导管末闭
E．二尖瓣狭窄
参考答案：D
—Would you like some juice or coffee?
—_____I really don't mind. [ ]
A. Either
B. Neither
C.Both
糖渍保存时，糖的质量分数一般控制在( )。
A．20%～60%
B．20%～30%
C．10%～30%
D．60%～80%
