空气辅助喷漆因为油漆雾化完全，因而空气中溶剂与油漆飞散得多，污染比较严重。
参考答案：对
The mean return of a portfolio is 20% and its standard deviation is 4%. The returns are normally distributed. Which of the following statements about this distribution are least accurate The probability of receiving a return:（）
A. of less than 12% is 0.025.
B. between 12% and 28% is 0.95.
C. in excess of 16% is 0.16.
下列天然石材中，何者耐碱而不耐酸
A．花岗岩 B．石灰岩 C．石英岩 D．文石
