移动支架施工要求移动支架总长一般为桥跨的（）倍。

A、1

B、2

C、2.5

D、3

轨道交通U形梁预制混凝土配合比水胶比控制在（）范围内，砂率为34%～44%。

具有一定肾脏毒性的头孢菌素是（）

A、头孢噻吩

B、头孢西丁

C、头孢曲松

D、头孢他定

E、头孢哌酮

简述一般的风险应对方法？

Though it is merely 1 to 3 percent of the population, the upper class possesses at least 25 percent of the nation s wealth. This has two segments; upper-upper and lower-upper. Basically, the upper-upper class is the "old rich"—families that have been wealthy for several generations—an aristocracy of birth and wealth. Their names are in the Social Register, a listing of acceptable members of high society. A few are known across the nation, such as the Rockefellers, Roose-velts, and Vanderbilts. Most are not visible to the general public. They live in grand seclusion(过 着显赫的退隐生活), drawing their income from the investment of their inherited wealth. In contrast , the lower-upper class is the " new rich". Although they may be wealthier than some of the old rich, the new rich have hustled(拼命干)to make their money like everybody else beneath their class. Thus their prestige is generally lower than that of the old rich, who have not found it necessary to lift a finger to make their money, and who tend to look down upon the new rich. However its wealth is acquired, the upper class is very rich. They have enough money and leisure time to cultivate an interest in the arts and to collect rare books, paintings, and sculptures. They generally live in exclusive areas, belong to exclusive social clubs, communicate with each other, and marry their own kind—all of which keeps them so distant from the masses that they have been called the out-of-sight class. More than any other class, they tend to be conscious of being members of a class. They also command an enormous amount of power and influence here and abroad, as they hold many top government positions, run the Council on Foreign Relations and control multinational corporations. Their actions affect the lives of millions.

All the following statements are true except that______.

A．the upper class owns at least a quarter of the country" s wealth

B．the "old rich" enjoy higher prestige than the "new rich"

C．the "old rich" isolate themselves and lead a lonely life

D．the upper-upper class is of aristocratic origin

糖皮质激素类药物的“四抗作用”是指（），（），（），（）。