问题 单项选择题

学家在查阅19世纪中期的一些文献,发现热气、臭气、烟气、毒气等字眼都是描写城市环境最为常见的词汇。该城市最有可能是()

A.伦敦

B.北京

C.莫斯科

D.东京

答案

参考答案:A

解析:[联系19世纪中期的阶段特征,可知材料所指为工业革命导致环境污染,选项中此时完成工业革命的城市只有伦敦,故A项符合题意;北京、莫斯科、东京此时均未完成工业革命,故B、C、D项错误。]

实验题

(18分)氨、氯气和溴是中学化学实验中的常见试剂:

(1)实验室利用反应:2NH3+3CuON2+3Cu+3H2O中反应物CuO和生成物H2O的质量可以测定铜的近似相对原子质量,实验装置(加热及夹持装置未画出)如下。实验开始时,应先点燃      (填‘‘A”‘‘B”)处酒精灯;c中碱石灰的作用为               

上述装置设计尚存在缺陷,应在          (填上述仪器字母序号)之间再加一个装置,请画出该装置(注明所需试剂)。

(2)实验室用Cl2从盐湖苦卤(富含K+、Ca2+、Mg2+、Br、SO、Cl等)中提取较纯净的氯化钾晶体及液溴,流程如下:

①步骤I中液体静置分层后,从分液漏斗中分离出无色溶液A的具体操作过程为          

②加入试剂x的目的是              ;步骤Ⅳ中试剂y的化学式为              

③步骤v中蒸发溶液D时需要的仪器除酒精灯、三脚架外还需                   

(3)Br2和FeCl3的稀溶液均呈黄色。将少量稀溴水滴入稀FeCl2溶液得黄色溶液,某同学设计实验验证二者混合能否发生反应:取少量混合溶液,加入淀粉碘化钾溶液,振荡溶液变蓝色,则二者未发生化学反应。该实验设计不正确,错误在于____       。设计合理实验检验溴水和FeCl2溶液是否发生化学反应(简要说明实验步骤、现象和结论)                  

阅读理解

阅读理解。

     In Britain and other countries, young people sometimes take a gap year, a year off between high school

and college. This idea never gained a big following in America. Recent news reports have suggested that

interest may be growing , though there are no official numbers.

     Charles Deacon, Dean of Admissions at Georgetown University in Washington, DC estimate that in the

current first-year class of 1600 students, only about 25 decided to take a year off. He says this number hasn't

changed much over the years.

     Mr.Deacon says the most common reason for taking a gap year is to have a chance to travel, but he says

inernational students may take a gap year to meet requirements at home for military duty.

     Some high school graduates see a year off as a chance to recover after twelve years of required education,

but it can also give students a chance to explore their interests. Students hoping to be doctors, for example,

could learn about the profession by volunteering in a hospital. Many colleges and universities support gap-year

projects by permitting students to delay their admission. Experts say students can grow emotionally and

intellectually as they work at something they enjoy.

     The Harvard admissions office has an essay on its Web site called “Time Out or Burn Out for the Next

Generation.” It praises the idea of taking time off to step back, think and enjoy gaining life experiences

outside the pressure of studies. It also notes that students are sometimes admitted to Harvard or other colleges

partly because they did something unusual with that time.

     Of couse, a gap year is not for everyone. Students might miss their friends who go on directly to college ,

and parents might worry that their children will decide not to go to college once they take time off. Another

concern is money. A year off, away from home, can be costly.

     Holly Bull's job is to specialize in helping students plan their gap year. She notes that several books have

been written about this subject. She says these books along with media attention and the availability of

information on the Internet have increased inerest in the idea of a year off, and she points out that many

gap-year programs cost far less than a year of college.

1. What is the passage mainly about?

A. If you want to go to an American university, take a gap year first.

B. More and more American students are choosing to take a year off.

C. It is likely that taking a gap year is becoming popular in America.

D. Americans hold different opinions towards students taking a gap year.

2. How many reasons for students' taking a gap year are mentioned in passage?

A. 2

B. 3

C. 4

D. 5

3. The esssay “time out or burn out for the next generation” suggests that ______.

A. every student must take a gap year before applying for a famous university

B. some famous universities encouage students to gain more life experiences

C. taking a gap year can make students free from life learning

D. the stress of studies does harm to the students' health

4. What can we learn from the passage?

A. Charles Deacon doesn't support the idea of the students' taking a gap year

B. Books and media have contributed to the students' inerest in school learning

C. Parents might disagree with the program, concerned about their children's future.

D. Experts agree taking a year off will benefit the students emotionally and physically.