XJX型浮选机是（）型浮选机。
A.机械搅拌充气式
B.机械搅拌自吸式
C.充气式
D.气体排出式
参考答案：B
There were some chairs left over____ everyone had sat down.
A．when
B．until
C．that
D．where
简述认股权证与可转换债券的相同之处和不同之处。
