粗酚间歇减压精馏的工艺如何精制粗酚？

一个控制器的输出同时送往两个或更多的执行器，而各个执行器的工作范围不同，这样的系统叫做（）控制系统。

A、分程

B、三冲量

C、串级

D、选择性

意外伤害保险的基本保障项目为（）。

A.死亡给付和医疗费用给付

B.残疾给付和医疗费用给付

C.死亡给付和残疾给付

D.死亡给付和医疗事故给付

Questions 21-25We are not who we think we are.The American self-image is suffused with the golden glow of opportunity. We think of the United States as a land of unlimited possibility, not so much a classless society but as a place where class is mutable-a place where brains, energy and ambition are what counts, not the circumstances of one’s birth.The Economic Mobility Project, an ambitious research initiative led by Pew Charitable Trusts, looked at the economic fortunes of a large group of families over time, comparing the income of parents in the late 1960s with the income of their children in the late 1990s and early 2000s. Here is the finding: "The ’rags to riches’ story is much more common in Hollywood than on Main Street. Only 6 percent of children born to parents with family income at the very bottom move to the top.That is right, just 6 percent of children born to parents who ranked in the bottom fifth of the study sample, in terms of income, were able to bootstrap their way into the top fifth. Meanwhile, an incredible 42 percent of children born into that lowest quintile are still stuck at the bottom, having been unable to climb a single rung of the income ladder.It is noted that even in Britain-a nation we think of as burdened with a hidebound class system-children who are born poor have a better chance of moving up. When the three studies were released, most reporters focused on the finding that African-Americans born to middle-class or upper middle-class families are earning slightly less, in inflation-adjusted dollars, than did their parents.One of the studies indicates, in fact, that most of the financial gains white families have made in the past three decades can be attributed to the entry of white women into the labor force. This is much less true for African-Americans.The picture that emerges from all the quintiles, correlations and percentages is of a nation in which, overall, "the current generation of adults is better off than the previous one", as one of the studies notes.The median income of the families in the sample group was $55,600 in the late 1960s; their children’s median family income was measured at $71,900. However, this rising tide has not lifted all boats equally. The rich have seen far greater income gains than have the poor.Even more troubling is that our notion of America as the land of opportunity gets little support from the data. Americans move fairly easily up and down the middle rungs of the ladder, but there is "stickiness at the ends" - four out of ten children who are born poor will remain poor, and four out often who are born rich will stay rich.

Which of the following statements is TRUE according to the passage

A．The US is a land where brains, energy and ambition are what counts.

B．Inequality persists between whites and blacks in financial gains.

C．Middle-class families earn slightly less with inflation considered.

D．Children in lowest-income families manage to climb a single rung of the ladder.

刚度是指材料抵抗（）的能力。

（）是危机处理的第一公众对象。

A、相关责任人

B、媒体

C、企业员工

D、受害者