搜题请搜索小程序“爱下问搜题”
问题 选择题

下列有关实验现象的描述与实验事实不相符的是

A．木炭在氧气中燃烧时发出白光

B．红磷在空气中燃烧时产生大量的白雾

C．硫在氧气中燃烧时发出明亮的蓝紫色火焰

D．一氧化碳燃烧产生蓝色火焰，生成使澄清石灰水变浑浊的气体

答案

答案：B

题目分析：红磷在空气中燃烧时生成的五氧化二磷是固体，所以现象应为形成浓浓的白烟而不是白雾。此项错误。

单项选择题

Modern industrial society grants little status to old people. In fact, such a society has a system of built-in obsolescence. There is no formal system for continuing our education throughout our life in order to keep up with rapidly changing knowledge. When our education and job skills have grown obsolete, we are treated exactly like those who have never gained an education or job skills and are not encouraged or given the opportunity to begin anew.As a society becomes more highly developed, the overall status of older people diminishes. Improved health technology creates a large pool of old people, who compete for jobs with the young. However, economic technology lowers the demand for workers and creates new jobs for which the skills of the aged are obsolete, forcing older people into retirement. At the same time, young people are being educated in the new technology and are keeping pace with rapid changes in knowledge. Finally, urbanization creates age-segregated neighborhoods. Because the old live on fixed incomes, they must often live in inferior housing. All these factors — retirement, obsolete knowledge and skills, inferior standards of living — lower the status of the aged in society.A century ago, when one could expect to live only to 50 or so, the life span more or less coincided with the occupation and family cycle. But today the average life span allows for fifteen to twenty years of life after these cycles. It appears that our life span is outpacing our usefulness in society.

By "a system of built-in obsolescence" the author means________.

A．no formal systems exist in modern industrial society

B．old people have no status in modern industrial society

C．young people have chances in modern industrial society

D．knowledge changes rapidly in modern industrial society
查看答案
问答题

[背景材料]
某大厦工程项目，建设单位与施工单位根据《建设工程施工合同文本》签订了工程的总承包施工合同，总承包商将该大厦工程项目的装饰装修工程分包给一家具有相应资质条件的某装饰装修工程公司。该装饰装修工程合同与该工程项目建设单位签订了该大厦工程项目的装饰装修施工合同。
该工程总承包施工单位在施工过程中发生以下事件。
事件一：基坑开挖后用重型动力触探法检查，发现基坑下面存在古墓。
事件二：基坑验槽时，总承包施工单位技术负责人组织、建设、设计、勘察、监理等单位的项目技术负责人共同检验，经检验基坑符合要求。
事件三：为了使水泥浆更具黏结力，旋喷桩在旋喷前3小时对水泥浆进行搅拌。
事件四：基坑回填过程中，施工总承包单位只检查了排水措施和回填土的含水量，并对其进行了控制。
[问题]

《建设工程施工合同文本》由哪几部分组成该文本的三个附件分别是什么
查看答案