问题 单项选择题

合流制管渠的设计流量一般为雨水设计流量、生活污水流量及工业废水流量三者之和,其中生活污水流量及工业废水流量是指______。

A.生活污水最大时流量、工业废水最大时流量
B.生活污水最大时流量、工业废水最大时平均流量
C.生活污水平均流量、工业废水最大时平均流量
D.生活污水平均流量、工业废水最大时流量

答案

参考答案:C

解析:参见《排水工程》(上册)(第四版)第4.2.1节,合流制管渠的设计流量一般为雨水设计流量、生活污水设计流量及工业废水设计流量三者之和。在实际水力计算中,由于这三部分流量同时发生的可能性很小,所以一般以雨水设计流量、生活污水的平均流量、工业废水最大班的平均流量之和作为合流制管渠的设计流量。

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Every year, wildfires(野火) destroy much forest land. homes are broken down, and thousands of people die. smokejumpers are stop helping to stop this.

Smokejumpers are a special kind of firefight. they jump from planes into areas that difficult to reach by car or on foot. they race to put out fires as fast as they can.

At a fire site, Smokejumpers first examine the land and decide how to fight the fire. their main goal is to stop fire from spreading. using basic tools such as shovels and axes, smokejumpers clear land of burnable material like plants and other dry material. they carry water with them too, but not much.

Although most smokejumpers are men, more women are joining. Most important are your weight and height. Smokejumpers in the U.S. for example ,must be 54 to 91 kilograms, so they don’t get hurt when they land, or get blown by strong winds.

Smokejumpers must be able to live in the wilderness. in Russia ,many smokejumpers know how to find food in the forest and even make simple furniture from trees.

They work is dangerous, the hours are long. But for these firefighters, smokejumpers isn’t just a job. They love being able to jump out of planes, fight fires, and live in the forest. As 28-year-old Russian smokejumpers Alexi Tishin says,“This is the best job for the strong and brave.”

小题1:What are Smokejumpers?

小题2:Where do the jump from?

小题3:What’s their main goal?

小题4:Why should they have proper weight?

小题5:What’s needed to be a smokejumpers?

单项选择题