问题 问答题

人们在工农业生产和生活中会产生大量污水,这些污水直接排人河流和湖泊后会产生严重的污染.那么该如何来处理这些污水呢?图是某中学环保小组的同学设计的污水处理流程图.        

(1)初步处理时,让污水流经沉淀槽,使一些较大的颗粒沉人底部形成矿泥.在这一处理中,应该让污水的流速______(填“快”或“慢”)一些.

(2)用于再处理的处理槽底部有一层厚厚的沙,这样可以除去一些不溶于水的物质,这种方法被称作______法.最后再通过追加处理以除去污水中的诸如重金属离子等有害成分.

答案

(1)水流的速度缓慢有利于较大的颗粒沉入底部.所以初步处理时,让污水流经沉淀槽,使一些较大的颗粒沉人底部形成矿泥.在这一处理中,应该让污水的流速慢一些.

(2)处理槽底部有一层厚厚的沙,可以除去一些不溶于水的物质,这种方法称为过滤.

故答案为:(1)慢.  

(2)过滤.

阅读理解

阅读理解。

     "Beijing, Toronto and Paris are the most important cities bidding for the Olympic Games of 2008," said

Richard W. Pound, the IOC's first vice president (副 * * ).

     "The host city of the Olympic Games of 2008 will be decided at the IOC meeting in Moscow in 2001.

Beijing is ready on its way because it nearly becomes the host of the Olympic Games of 2000, and Toronto

and Paris also have strong power (竞争力)," said Pound at an IOC meeting.

     After ten cities are interested in bidding for the Olympic Games of 2008. They are Beijing, Toronto, and

Paris. Some of other cities are Osaka, Havana, Istanbul and Cairo.

     For the first time, the host city will be decided without IOC members visiting the places. The bidding

scandals (丑闻) of the Salt Lake City have made the IOC find new ways of bidding. That is why the IOC

members will not be allowed to visit the bidding cities.

1. Richard W. Pound _________.

A. can decide where to hold the Olympic Games

B. knows the most about the Olympic Games

C. is one of the IOC's presidents

D. will visit the most important bidding cities

2. In 2001, _________.

A. there'll be the Olympic Games in Moscow

B. the host city of the Olympic Games of 2008 will be decided

C. the IOC members will have more meetings

D. more and more cities are going to bid for the Olympic Games

3. The underlined parts "bidding for" and "host city" may mean ________.

A. 申办; 主办城市

B. 寻求; 美丽城市

C. 建立;奥运之都

D. 盼望;都市风情

4. Osaka, Havana, Istanbul and Cairo are ________.

A. much smaller than Beijing, Toronto and Paris

B. waiting to be visited by IOC members

C. going to the IOC meeting in Moscow

D. also bidding for the Olympic Games of 2008

5. Which of the following is true?

A. Beijing has strong power to bid for the Olympic Games of 2008.

B. It is the first time for Toronto and Paris to bid for the Olympic Games.

C. The bidding scandals are still not known by the bidding cities.

D. The IOC has started new ways of bidding since 2000.

单项选择题