采用核子密度湿度仪测定沥青混合料面层的压实密度时采用透射法。( )
参考答案：错
解析： 采用核子密度湿度仪测定沥青混合料面层的压实密度时采用散射法。
煤是不均质的（），由（）和（）两部分组成。
The most likely motivation for a speculator to sell a security short is based on the investor’s belief that the:（）
A. security is overpriced.
B. required rate of return on the security will decline.
C. short sale proceeds could be invested for extra returns.
