节能工作的重要意义是什么？

多数前才缺失的可摘义齿设计中，在牙弓的后段放置间接固位体，以对抗义齿的翘动。以下最合适的卡环设计是（）

A.间隙卡环

B.长臂卡环

C.回力卡环

D.对半卡环

E.双臂卡环

下表是某种常见金属的部分性质。

将该金属投入稀盐酸中，可产生大量的无色气体，根据上述信息回答下列问题：

（1）试推断该金属可能的一种用途                    。

（2）该金属的活动性比铜                  (填“强”或“弱”)。

（3）完成并填写下列实验“探究该金属与铁的活动性强弱比较”的实验报告。

D

At age 61, identical twins Jeanne and Susan no longer look exactly alike. Susan smoked for many years and is an admitted sun worshipper, whose habits Jeanne does not share. A new study of twins suggests you can blame those coarse(粗糙的)wrinkles, brown or pink spots on too much time in the sun, smoking, and being overweight.

Because twins share genes, but may have different exposures to environmental factors studying twins allows an “opportunity to control for genetic susceptibility(易受影响性),” Dr. Elma D. Baron, at Case Western Reserve School of Medicine in Cleveland, Ohio, and his colleagues explain in the latest issue of Archives of Dermatology.

Their analysis of environmental skin-damaging factors in 65 pairs of twins hints that skin aging is related more to environment and lifestyle than genetic factors.

But when it comes to skin cancer, the researchers say their findings support previous reports that both environment and genes affect skin cancer risk.

Baron’s team examined facial skin of 130 twins, 18 to 77 years old, who lived mostly in the northem Midwest and Eastern regions of the US, who were attending the Twins Days Festival in Ohio in August 2002. At this time, each of the twins also separately reported how their skin burned or tanned(晒黑)without sunscreen, their weight, and their history of skin cancer, smoking, and alcohol drinking. The study group consisted of 52 fraternal(异卵双生)and 10 identical twin pairs, plus 3 pairs who were unsure of their twin status.

From these data, the researchers noted strong ties, outside of twin status, between smoking, older age, and being overweight, and having facial skin with evidence of environmental damage. By contrast, sunscreen use and drinking alcohol appeared related to less skin damage.

Baron and his colleagues say the current findings, which highlight ties between facial aging and potentially avoidable environmental factors—such as smoking, being overweight, and unprotected overexposure to the sun’s damaging rays—may help motivate people to minimize these risky behaviors.

67．Which of the following is true according to the passage?

A．Jeanne and Susan share all the habits including smoking.

B．Skin aging is related more to environment and lifestyle than genetic factors.

C．Only identical twins can take part in the research.

D．Sunscreen use cannot help people have less skin damage.

68．Why did Baron’s team do the research on twins?

A．Twins are more likely to suffer from skin cancer.

B．It may guarantee the research is not influenced by genetic factors.

C．It gives others an opportunity to control twins’ genes.

D．It helps find twins are exposed to different environments.

69．What can you infer from the last paragraph?

A．This research makes people aware of dangerous lifestyles.

B．The environmental factors are unavoidable.

C．Being exposed to the sun is absolutely damaging.

D．There is little relationship between skin aging and environment.

70．The passage is mainly concerned with___________

A．skin cancer and environment

B．identical twins research

C．aging skin and environmental factors

D．genes and lifestyles

Uganda is a country in East Africa and,as in many such countries,a high percentage of the population,about 80 percent,are village-dwellers living in huts,which are often no bigger than a garage. The walls of the huts are made of mud,which is held together by reeds and sticks,and the roofs of the older ones are thatched（覆盖）with grass,although an increasing number of newer village houses have roofs made from corrugated（波纹形的）iron.

Several generations of the same family live together in the huts,which are usually divided into two sections by a curtain. The inner section,the one furthest from the open door of the hut,is where everyone sleeps and food is prepared and served in the outer part. If the family owns chickens or goats,they are kept in a small room attached to the main house.

Food is usually prepared on open fires although some people prefer to cook inside. However,this is quite dangerous and also means that the walls of the hut are stained by smoke and the atmosphere is acrid. The family sit in a circle on mats while they eat.

Newer village houses are almost always made of corrugated iron and are bigger,with one or two separate bedrooms and the kitchen in a smaller building beside the main house. But,old or new,the houses are not powered by electricity,and all homes are lit by paraffin（石蜡）candles called “tadobba”.

Nor is there any running water in the houses. Some villages have their own well,but in many cases,collecting water involves a long and arduous walk to a river or spring,carrying plastic containers or pots made of clay.

Children are the ones who have to fetch water,and they have to do this early in the morning before they go to school,or in the evening when they come home. They often have to climb high hills or walk through valleys with narrow paths through dense vegetation. It is no surprise that they grow up muscular and fit after such daily exercise,walking for several kilometres carrying such heavy weights.

小题1:Most Ugandans live        .

A．with their whole family in large mud houses in the countryside

B．in towns in small houses made of mud and iron

C．in villages in small houses made of wet earth,grass and wood

D．With their parents and children as well as their chickens and goats小题2:Where is food usually prepared?

A．In the kitchen.

B．On the floor in the middle of the house.

C．On fires in front of the hut.

D．In a small room attached to the main house.小题3:How are the old and new houses the same?

A．Both of them have roofs made of corrugated iron.

B．Neither of them have a garage or kitchen.

C．Neither of them have electricity,lights or running water.

D．Both of them have water inside but no electric light.小题4:The majority of Ugandan children have to          .

A．go to a well or a river and often carry it for a long distance

B．do a lot of work cooking and carrying water

C．collect water on the way home from school

D．get water out of their own well

干式消弧线圈环氧树脂表面及端部应光滑平整，无裂纹或损伤变形。