应用蒸汽与凝结水温度差的原理工作的疏水器是（）疏水器。
A、机械型
B、恒温型
C、脉冲型
D、热动力式
参考答案：B
“Three” is three times _________ “one” and twice _________ “one”.
A．as much as, as much as
B．more than, more than
C．as much as, more than
D．more than, as much as
愈伤组织不能够进行分裂和生长。
