Have you ever walked outside thinking it was one temperature but quickly discovered it felt colder? That is because of the “wind chill” effect.
Wind chill is how cold people and animals feel when they are outside, not the actual temperature on the thermometer(温度计). It is based on how quickly your body loses heat when it is exposed to wind and cold. When the wind is strong, your body quickly loses heat, making the temperature of your skin drop.
When scientists first started calculating wind chill, they used research conducted in 1945 by explorers to Antarctica who measured how quickly water froze outside.
But water freezes faster than exposed skin, so the wind chill index based on that data wasn’t accurate.
In 2001, the US government began to measure wind chill more precisely by testing how quickly people’s skin froze.
Twelve volunteers were placed in a chilled wind tunnel. Equipment was stuck to their faces to measure the heat flow from their cheeks, forehead, nose and chin while they walked three miles per hour on a treadmill(跑步机).
The experiment revealed how quickly exposed skin can be damaged, particularly unprotected areas like your fingers, toes, the tip of your nose and your ear lobes. In fact, 40 percent of your body heat can be lost through your head! Signs you might have frostbite(冻疮) are when the skin turns white or pale and you lose feeling in that area.
The information collected from the volunteers helped scientists work out the math to compute wind chill. It involves wind speed and air temperature.
If, for example, the temperature outside is zero degrees Fahrenheit and the wind is blowing at 15 miles per hour, the wind chill is calculated at 19 degrees below zero. At that wind chill temperature, exposed skin can freeze in 30 minutes.
You can find a calculation table at www.nws.noaa.gov/om/windchill/index.shtml.
Experts advise in cold weather that you wear loose-fitting, lightweight, warm clothing, worn on top of each other. Air caught between the clothes will keep you warm. The best cold-weather coats have head coverings made of woven material that keep out water. So next time the temperature drops and you want to play outside, listen to your parents when they tell you to wrap up warm!
【小题1】 According to the text, wind chill _______.

Have you ever walked outside thinking it was one temperature but quickly discovered it felt colder? That is because of the “wind chill” effect.
Wind chill is how cold people and animals feel when they are outside, not the actual temperature on the thermometer(温度计). It is based on how quickly your body loses heat when it is exposed to wind and cold. When the wind is strong, your body quickly loses heat, making the temperature of your skin drop.
When scientists first started calculating wind chill, they used research conducted in 1945 by explorers to Antarctica who measured how quickly water froze outside.
But water freezes faster than exposed skin, so the wind chill index based on that data wasn’t accurate.
In 2001, the US government began to measure wind chill more precisely by testing how quickly people’s skin froze.
Twelve volunteers were placed in a chilled wind tunnel. Equipment was stuck to their faces to measure the heat flow from their cheeks, forehead, nose and chin while they walked three miles per hour on a treadmill(跑步机).
The experiment revealed how quickly exposed skin can be damaged, particularly unprotected areas like your fingers, toes, the tip of your nose and your ear lobes. In fact, 40 percent of your body heat can be lost through your head! Signs you might have frostbite(冻疮) are when the skin turns white or pale and you lose feeling in that area.
The information collected from the volunteers helped scientists work out the math to compute wind chill. It involves wind speed and air temperature.
If, for example, the temperature outside is zero degrees Fahrenheit and the wind is blowing at 15 miles per hour, the wind chill is calculated at 19 degrees below zero. At that wind chill temperature, exposed skin can freeze in 30 minutes.
You can find a calculation table at www.nws.noaa.gov/om/windchill/index.shtml.
Experts advise in cold weather that you wear loose-fitting, lightweight, warm clothing, worn on top of each other. Air caught between the clothes will keep you warm. The best cold-weather coats have head coverings made of woven material that keep out water. So next time the temperature drops and you want to play outside, listen to your parents when they tell you to wrap up warm!

1. 1.

   According to the text, wind chill _______.

   1. A.
      means how fast exposed skin freezes
   2. B.
      doesn’t affect your head as much as other body parts
   3. C.
      changes according to the temperature on the thermometer
   4. D.
      changes from person to person depending on their health
2. 2.

   When might a person have frostbite according to the passage?

   1. A.
      When his skin turns red and he loses feeling in that area.
   2. B.
      When he is running faster and he is losing strength quickly.
   3. C.
      When his face is exposed and quickly loses heat even indoors.
   4. D.
      When his skin turns pale and he has no feeling in that area.
3. 3.

   What factors influence wind chill?

   1. A.
      A person’s body temperature and will speed.
   2. B.
      Wind speed and a person’s strength.
   3. C.
      Air temperature and wind speed.
   4. D.
      The location and air temperature.
4. 4.

   What can we conclude from the passage?

   1. A.
      It was in 1945 that scientists first began to calculate wind chill.
   2. B.
      Compared with water, people’s exposed skin freezes more slowly.
   3. C.
      The wind chill index based on Antarctica data is considered a standard.
   4. D.
      With the development of technology, many previous researches have been proven wrong.

But what is teacher quality? How can one measure it reliably?

An analysis is issued on a sample of data from a Texas school district. Experts argue convincingly that teacher effectiveness should be measured by students’ gains on standardized tests: Mr. Smith is probably a better teacher than Ms. Brown if his students consistently improve their test scores more than hers do.

Though this approach is appealing, there are tricky issues. For example, what if Ms. Brown teaches in a school where students score so high there is little room for improvement?

The authors try to correct for this problem, as well as other sorts of measurement issues, to generate a measurement of teacher effectiveness. The paper is primarily concerned with how this measure is related to other observable characteristics.

The first finding is that there is a large variation in teacher effectiveness: some teachers consistently have a larger impact on their students’ achievement than others.

Second, easily observable characteristics like having a master’s degree or a passing score on the teacher certification exam are not correlated关联 with teacher effectiveness.

Then what does matter? The most important single influence is experience: first-year teachers are much less effective than others. The second year is significantly better, and by the fourth year, most teachers hit their stride.

It is not entirely clear whether this experience effect is learning by doing (the more you teach, the more effective you become) or survival of the fittest (those who are not good at teaching tend to drop out early.)

From my reading of the paper, both effects appear important and there is no simple answer. The data do suggest, however, that teacher effectiveness is pretty clear by the end of the second year, so the information to make an informed decision is available at that time.

The authors also investigate the contentious 有争议的issue of racial matching of students and teachers. Here they find strong evidence that minority teachers tend to be more effective with minority students. Again, it is unclear whether this is because of a role model effect (students respond better to a teacher of their own race) or an empathy effect 移情效应(teachers empathize better with students of their own race) or something else entirely.

The authors also look at teacher mobility. There is some evidence that teachers who quit teaching or switch schools tend to be below average in effectiveness. This is consistent with the survival-of-the-fittest model.

1.The schoolmaster could decide wisely whether to further employ the teacher by the end of the ______.

A. the first year          B. the second year             C. the third year        D. the fourth year

2.The phrase “hit their stride” most probably means “______”.

A. reach their normal level                                    B. become confident

C. walk with long steps                                            D. get bored

3.The author of this passage holds the view that ______.

A. teachers will perform better with time passing

B. ineffective teachers should leave earlier rather than later

C. teacher’s effectiveness is apparent after a couple of years

D. a master’s degree will improve teacher’s effectiveness

4.Why do black teachers tend to be more effective with black students?

A. Students fell secure, so they respond better.

B. Teachers sympathize with students of their own race.

C. There are entirely some other identified reasons.

D. The reasons are far from clear and definite.

5.Which of the following may serve as the best title?

A. The Quality of Teaching

B. Impact of Teacher Quality on Student Learning

C. Different Sorts of Measurement Issues

D. Survival-of-the-fittest Model vs. Learning-by-doing Model

A dense wave of smog began in the Chinese city of Harbin and the surrounding Heilongjiang, Jilin, and Liaoning Provinces on 20 October 2013. Unseasonably warm temperatures with very little wind across northeastern China coincided with the smoke from local farmers’ burning straws and the start-up of Harbin’s coal-powered central heating system.

Record densities of fine particulates(微粒)were measured in the city. In Harbin, the levels of PM2.5 (particulate matter) rise to 1,000 micrograms per cubic meter, worse than Beijing’s historic highs. Visibility was reduced to below 50m in parts of Harbin, and below 500m in most of the neighbouring Jilin Province. On Fa Yuen Street in Harbin, visibility of less than 5m was reported. The smog reduced after October 23, 2013 and completely broke up on October 28, 2013 by the first local snow and icy rain due to a cold front moving in from Russia.

Harbin lies in the north of China where winter temperatures can drop to -40℃, demanding a six-month heating season. Daily particulate levels of more than 40 times the World Health Organization recommended maximum level were reported in parts of Harbin. The smog remained till 23 October, when almost all monitoring stations in Heilongjiang, Jilin, and Liaoning Provinces reported readings above 200μg/m³forPM2.5. PM2.5 is the amount of particulate matter less than 2.5 micrometers in diameter in the air, with the WHO recommending a maximum 24-hour mean (平均值) of 25 micrograms per cubic meter (μg/m³). On the morning of 25 October, PM2.5 measurements in Harbin had fallen to an average of 123μg/m³.

All highways in the surrounding Heilongjiang Province were closed. In Harbin, all primary and middle schools were closed for three days and authorities stopped flights at the airports. Hospitals reported a 23 percent increase in admissions for breathing problems. However, this smog will have no influence on Harbin Ice Festival events later in December 2013.

Air pollution in Chinese cities is of increasing concern to China’s leadership. Particulates in the air can affect human health and also have influences on climate and rainfall. Pollution from the burning of coal has reduced life expectancy by 5.5 years in the north of China, as a result of heart and lung diseases.

1.One cause of the heavy smog in the northeastern Chinese cities may be _____.

A. the lasting cold weather                         

B. farmers’ burning of forests

C. too much strong wind                              

D. the start-up of heating system

2.One serious influence of the heavy smog was that_____.

A. Harbin Ice Festival would be cancelled    

B. highways in Heilongjiang were free of charge

C. all flights at the airport were cancelled    

D. doctors in hospitals were kept from working

3.The harmful smog was most serious on ______.

A. October 20      B. October 23    C. October 25     D. October 28

4.What measure might be practical to reduce the happening of heavy smog?

A. Forbidding people to own their private cars.    

B. Advocating people having one meal a day.

C. Using natural gas to cook instead of coal.      

D. Encouraging family’s coal-fired heating.