[单项选择]随着啤酒生产和销售旺季的来临，一些啤酒生产企业相继抛出啤酒中含甲醛有害健康的论调，并宣称自己已经取消使用甲醛，改用其他物质代替，此举在业内引起一番激烈的争论。有的企业更是借用中国酿酒工业协会啤酒分会的旗号抛出“甲醛有害论”。针对这种情况，中国酿酒工业协会啤酒分会发表声明，指出微量甲醛广泛存在于天然食品中，啤酒所含甲醛和天然食品相比，含量属低量范畴。甲醛作为食品工业加工允许使用的助剂，在啤酒产品中的含量都在较低范围，对身体健康无害。
这段文字意在表明( )。
A. 天然食品中广泛含有微量甲醛
B. 啤酒生产无禁用甲醛规定
C. 啤酒微含甲醛对人体无害
D. 啤酒生产企业哗众取宠

66. __________.
Demand theory is based on a simply generalization about customer behavior that has been observed for centuries, that almost people would regard as "common sense". Generally speaking, if a good or service becomes more expensive, consumers are less likely to buy it. So, the price of oil more than doubled in 1999, the demand for oil would fall. How much did the demand for oil fall would depend on the elasticity of the demand for oil. Economists describe the demand for oil response as relatively inelastic. So, the fall was not large.
67. __________.
A substantial rise in the price of oil would affect the demand for oil tankers and coal in 1999.
68. __________.
The use of coal is the same as oil. When file price of oil rises, fewer people will use oil and more people will use coal. In Economics, coal is a substitute good of oil, the price of oil rises, and the demand for oil falls, the demand for coal increases. As