概念是对现象的抽象，它是一类事物的（）在人们头脑中的反映

学过《古代中国的政治制度》这一单元后，某班四位同学分别撰写历史研究小论文，其中论文标题出现史实错误的是 [ ]

A．浅议中国早期国家政治制度的创立者——大禹

B．趣谈周武王与分封制

C．论隋唐三省制度对中国历史的影响

D．论清代丞相与军机大臣的权力制衡

（一）

某施工单位承接了农村公路的5×16m简支板桥施工项目，桥梁上部结构为先张法预应力空心板，下部结构为双柱式桥墩，基础为桩基础，桥面面层为5cm厚沥青混凝土，采用租赁摊铺机摊铺。

桥头附近为砂性黏土，地势平坦，施工单位拟在此布置预制梁场，所需普通工人主要在当地雇用。当桩基础施工完毕后按规定进行了完整性检测。

在施工中发生了如下事件：

事件一：施工单位购买了三套千斤顶，为使用方便，千斤顶、油泵随机组合起来张拉预应力钢绞线。由于工期紧，新设备购买后立即投入使用。

事件二：在桥面施工过程中，施工单位安装伸缩缝后即进行5cm厚沥青混凝土施工，要求摊铺机匀速行驶，技术员随时检查高程及摊铺厚度。

问题：

结合背景资料，写出施工单位需要签订哪些合同？

关于他巴唑治疗甲亢的作用机制，下述哪一点是错误的（）

A.抑制碘的活化

B.抑制甲状腺过氧酶活性

C.抑制酪氨酸碘化

D.抑制碘化酪氨酸的缩合

E.抑制甲状腺素的释放

属于苯丙二氮杂卓的药物有（）

A卡马西平

B奥沙西泮

C地西泮

D扑米酮

E舒必利

Children are a relatively modem invention. Until a few hundred years ago they look like adult, wearing grown-up clothes and grown-up expressions, performing grown-up tasks. Children did not exist because the family as we know it had not evolved.
Children today not only exist; they have taken over in no place more than in America, and at no time more than now. It is always Kids Country here. Our civilization is child-centered, child-obsessed. A kid’s body is our physical ideal. In Kids Country we do not permit middle-aged. Thirty is promoted over 50, but 30 knows that soon his time to be overtaken will come.
We are the first society in which parents expect to learn from their children. Such a topsy-turvy situation has come to abort at least in part because, unlike the rest of the world, ours is an immigrant society, and for immigrants the only hope is in the kids. In the Old Country, that is, Europe, hope was in the father, and how much wealth he could accumulate and pass along to his children. In the growth pattern of America and its ever- expanding frontier, the young man was ever advised to GO WEST; the father was ever inheriting from his son. Kids Country may be the inevitable result.
Kids Country is not at all bad. America is the greatest country in the world to grow up in because it is Kids Country. We not only wear kids clothes and eat kids food; we dream kids dreams and make them come tree. It was, after all, a boys’ game to go to the moon.
If in the old days children did not exist, it seems equally true today that adults, as a class, have begun to disappear, condemning all of us to remain boys and girls forever, jogging and doing push-ups against eternity.

The sentence "Children are a relatively modem invention" underlined in Paragraph 1 means that children ______ .

A．were exactly the same as adults a few hundred years ago
B．did not exist at that time because there were no families yet
C．were not different from adults in physical appearance
D．were not different from adults