客运专线铁路CRTSⅡ型板式无砟轨道混凝土轨道板，每个台座制作混凝土抗压强度试件组数（）。
A、1组；
B、2组；
C、3组。
参考答案：C
回流比表达式中的L表示塔顶产品采出量。
Life expectancy among adults 45 and 65 years of age by family income, sex, and race: United States, average annual 1979-89
A sequence of numbers begins 1, 1, 1, 2, 2, 3 and then repeats this pattern forever. What is the sum of the 135th, 136th, and 137th numbers in the sequence
