某元素X的气态氢化物的化学式为HX，则X的最高氧化物的水化物的化学式为 [ ]
A. H2XO4
B. H3XO4
C. HXO3
D. HXO4
答案：D
简述结节点形成的四种情况？
Most of the differences among companies with respect to quality of earnings are addressed when companies are compared using:（）
A. price to earnings ratios.
B. price to cash flow ratios.
C. both price to earnings ratios and price to cash flow ratios.
