饱和蒸汽压力越大，离心泵吸入高度（）。
A、无影响
B、不变
C、大
D、小
参考答案：D
填“可能”或“不可能”
从放有4个白球和1个黑球的盒子里任意摸出1个球，( )是黑球，( )是蓝球。
An analyst does research about execution mechanisms. With respect to market structures, currencies are most likely traded in a market that is:（）
A. quote driven.
B. brokered.
C. order driven.
