More than 60 years after scientists made big discoveries about the structure of DNA, 20 students at US Coretta Scott King Young Women’s Leadership Academy gained insight（了解）into some of the molecular（分子的）mysteries that make them who they are.
Last fall, while studying life sciences, the girls sent samples（样本）of their DNA off to Living DNA, a DNA testing company. The test results became known last week and they left a big impression on the students, who were able to make real-world connections to topics they have been studying all semester long, including genotypes（基因型）.
“Students were able to maturely（成熟地）look at their results and apply what they learned in science. It’s about bringing learning to life,” said Laura Pena, the STEM program teacher.
For most of the girls, the DNA test was their ancestry（血统）. Sitting with her mom, Amariah Caudle, 15, looked with her mouth wide open at the charts showing her results. She was surprised that her European ancestry was only 13 percent. Her mother, Janell Caudle, was surprised it was that high.
“I didn’t think a trace（痕迹）would show up in her,” she said. “After many generations, this is still showing up in our bloodline（血统）. I was shocked by the science of it all.”
DNA has a power to engage people, said Diahan Southard, Living DNA community manager. Southard believes the program gives students an understanding of DNA at an important moment, when they are still young enough to absorb lessons and change their values.
Elianed Guzman, 14, said she knew little about her family except that they were from Mexico. She described in her native Spanish how surprised she was to learn that she shared genetic DNA with people in China, Japan and Korea.
As the girls sat in small groups to examine their results, with reactions ranging from confusion to surprise, they began to understand what it all means.
“Now I know I have family from everywhere,” said Amariah.
【小题1】Scientists made big discoveries about the structure of DNA possibly________.| A．in the 1910s | B．in the 1930s | C．in the 1950s | D．in the 1990s |
| A．Anxious. | B．Doubtful. | C．Impressed. | D．Calm. |
| A．People had the opportunity to test their DNA. | B．The European trace showed up in Amariah’s DNA. |
| C．Amariah possibly had European ancestry. | D．Amariah shared genetic DNA with people from Asia. |
| A．It helps students understand their DNAs. | B．It has a great power to bring people together. |
| C．It will change their students’ DNAs. | D．It should be introduced to more people around the country. |
| A．People need to accept who they are. | B．We should learn more about family history. |
| C．People’s personalities can be explained by their bloodlines. | D．People from all over the world are connected with each other. |
| A．Our amazing past | B．Our amazing present | C．Our amazing future | D．Our past, present and future |
C
Australia is nearly 7.7 million square kilometres.It's the sixth largest country in area after Russia，Canada，China，the United States and Brazil.
There are rainforests and large plains in the north，snowfields in the southeast，desert(沙漠) in the centre and croplands in the east，south and southwest.About one third of the country lies in the tropics(热带地区)．Australia has a coastline of 36，735 km if it were possible to drive non－stop along the whole coast at 60 km/h，it would take about 24 days to complete the trip.
Australia is the world's smallest continent(洲) and the sixth largest country being equal(相等的) in area to the USA without Alaska.The continent is one of the oldest lands.It is more than 3，000 million years old，and it is the flattest of the continents.
The population of Australia is more than 20 million.It is one of the world's most urbanized countries，with about 70% of the population living in the ten largest cities.Most of the population is concentrated(集中) along the eastern seaboard and the southeastern corner of the continent.
【小题1】Australia is smaller in area than________.| A．France | B．Britain |
| C．Japan | D．Canada |
| A．rainforests | B．desert |
| C．croplands | D．snowfields |
| A．工业化的 | B．现代化的 |
| C．城市化的 | D．农业化的 |
| A．About two thirds of the country lies in the tropics. |
| B．Australia has a long history of more than 5，000 million years. |
| C．About 20% of the population in Australia live in the cities. |
| D．It would take about 24 days to drive along the whole coast of Australia. |
| A．oldest | B．smallest | C．flattest | D．coldest |
 ●Male-to-female ratio(比例，比率) 105.07 ●sex ratio at birth 111.3 Age groups ●0—14 17.95% (up 1.35 percentage points from 2010) ●15—59 63.35% (down 6.79 percentage points from 2010) ●60 and above 18.7% (up 5.44 percentage points from 2010) |
According to the UN’s traditional standard, once a country’s or a region’s old people over 60 years old take up 10% of the total population, the country or the region will be regarded to enter an aging society.
【小题1】From the chart above, we can’t know ________.| A．the total population | B．death rate | C．the male-to-female ratio |
| A．China is stepping into an aging society |
| B．most of the Chinese population are above 60 |
| C．there are more newborn girls than newborn boys now |
The World Population Prospects (展望) 2022 report says: The population in the world reached 8 billion (十亿) on November 15, 2022. And the number will increase in the next ten years, although at a slower speed.
The population in the world is expected to rise to about 8.5 billion by 2030, 9.7 billion by 2050, peak (峰值) at about 10.4 billion in the 2080s, and stay there until 2100, the report says.
World population growth peaked at 2.1 percent between 1962 and 1965, and since then it has fallen quickly to less than 1 percent in 2020.
The UN predicts that population growth could fall to about 0.5 percent by 2050 as fertility rates (生育率) continue to fall.
On the other hand, people can live much longer than before, from 63.8 years in 1990 to 72.8 years in 2019, and will reach 77.2 years in 2050. At that time, 16 percent of the population will be 65 years or older.
China and India have the largest population in the world, with 1.4 billion people each. But India will have the largest population in 2023 and reach 1.7 billion people by 2050.
【小题1】What will be the population in the world in 2091 according to the text?| A．8.5 billion. | B．9.7 billion. | C．8 billion. | D．10.4 billion. |
| A．The old care will be a serious problem. | B．The population will increase quickly. |
| C．China will still have the largest population. | D．People can reach 72.8 years in 2050. |
| A．The serious problem of population. | B．The prediction of population growth. |
| C．Some ways to control population. | D．The population growth in China. |
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