（）行业的特点是销售增长缓慢，市场占有率竞争加剧。
A.新兴行业
B.成熟行业
C.衰退行业
D.稳定行业
参考答案：B
All else equal, which of the following would most likely cause a firm's price-earnings ratio to decline（）
A. The level of inflation is expected to decline.
B. The dividend payout ratio increases.
C. The yield on Treasury bills increases.
乙炔（C2H2）是一种重要的化工原料，实验室常用碳化钙（CaC2）与水反应制取乙炔，该反应方程式为：CaC2+2H2O→Ca（OH）2+C2H2↑．若要制取13g乙炔气体，需要碳化钙的质量是多少克？
