问题 单项选择题

城镇配水管网宜设计成(),当允许间断供水时,可设计为(),但应考虑将来连成()的可能性。

A、环状管网;树状管网;环状管网

B、树状管网;环状管网;树状管网

C、树状管网;树状管网;环状管网

D、树状管网;环状管网;环状管网

答案

参考答案:A

解析:A。城镇供水安全性十分重要,一般情况下宜将配水管网布置层环状,当允许间断供水时,如城市新规划区处在建设初期,或限于投资,一时不能形成环状管网,可按树枝状管网设计,但应考虑将来连成环状管网管网的可能。

填空题
单项选择题

Almost every day the media discovers an African American community fighting some form of environmental threat from land fills, garbage dumps, petrochemical plants, refineries, bus depots, and the list goes on. For years, residents watched helplessly as their communities became dumping grounds.
But citizens didn’t remain silent for long. Local activists have been organizing under the mantie of environmental justice since as far back as 1968. More than three decades ago, the concept of environmental justice had not registered on the radar screens of many environmental or civil rights groups. But environmental justice fits squarely under the civil rights umbrella. It should not be forgotten that Dr. Martin Luther King Jr. went to Memphis on an environmental and economic justice mission in 1968, seeking support for striking garbage workers who were underpaid and whose basic duties exposed them to environmentally hazardous conditions.
In 1979, a landmark environmental discrimination lawsuit filed in Houston, followed by similar litigation efforts in the 1980s, rallied activists to stand up to corporations and demand government intervention.
In 1991, a new breed of environmental activists gathered in Washington, D.C. , to bring national attention to pollution problems threatening low-income and minority communities. Leaders introduced the concept of environmental justice, protesting that Black, poor and working-class communities often received less environmental protection than White or more affluent communities. The first National People of Color Environmental Leadership Summit effectively broadened what "the environment" was understood to mean. It expanded the definition to include where we live, work, play, worship and go to school, as well as the physical and natural world. In the process, the environmental justice movement changed the way environmentalism is practiced in the United States and, ultimately, worldwide.
Because many issues identified at the inaugural summit remain unaddressed, the second National People of Color Environmental Leadership Summit was convened in Washington, D.C. , this past October. The second summit was planned for 500 delegates ; but more than 1,400 people attended the four-day gathering.
"We are pleased that the Summit Ⅱ was able to attract a record number of grassroots activists, academicians, students, researchers, planners, policy analysts and government officials. We proved to the world that our movement is alive and well, and growing," says Beverly Wright, chair of the summit. The meeting produced two dozen policy papers that show powerful environmental and health disparities between people of color and Whites.

The new breed of environmental activists differed from the previous activists in that ______.

A.they noticed environmental disparities between the rich and the poor

B.they cried for government intervention in saving the environment

C.they knew what "the environment" really meant to the White people

D.they practiced environmentalism outside as well as within the U. S.