3 . How does an ecosystem (生态系统) work? What makes the populations of different species the way they are? Why are there so many flies and so few wolves? To find an answer, scientists have built mathematical models of food webs, noting who eats whom and how much each one eats.

With such models, scientists have found out some key principles operating in food webs. Most food webs, for instance, consist of many weak links rather than a few strong ones. When a predator (掠食动物) always eats huge numbers of a single prey (猎物), the two species are strongly linked; when a predator lives on various species, they are weakly linked. Food webs may be dominated by many weak links because that arrangement is more stable over the long term. If a predator can eat several species, it can survive the extinction (灭绝) of one of them. And if a predator can move on to another species that is easier to find when a prey species becomes rare, the switch allows the original prey to recover. The weak links may thus keep species from driving one another to extinction.

Mathematical models have also revealed that food webs may be unstable, where small changes of top predators can lead to big effects throughout entire ecosystems. In the 1960s, scientists proposed that predators at the top of a food web had a surprising amount of control over the size of populations of other species—including species they did not directly attack.

And unplanned human activities have proved the idea of top-down control by top predators to be true. In the ocean, we fished for top predators such as cod on an industrial scale, while on land, we killed off large predators such as wolves. These actions have greatly affected the ecological balance.

Scientists have built an early-warning system based on mathematical models. Ideally, the system would tell us when to adapt human activities that are pushing an ecosystem toward a breakdown or would even allow us to pull an ecosystem back from the borderline. Prevention is key, which scientists says because once ecosystems pass their tipping point (临界点), it is remarkably difficult for them to return.

1. What have scientists discovered with the help of mathematical models of food webs?

A．The living habits of species in food webs.

B．The rules governing food webs of the ecosystems.

C．The approaches to studying the species in the ecosystems.

D．The differences between weak and strong links in food webs.

2. A strong link is found between two species when a predator ______.

A．has a wide food choice	B．can easily find new prey
C．sticks to one prey species	D．can quickly move to another place

3. What will happen if the populations of top predators in a food web greatly decline?

A．The prey species they directly attack will die out.

B．The species they indirectly attack will turn into top predators.

C．The living environment of other species will remain unchanged.

D．The populations of other species will experience unexpected changes.

4. How does an early-warning system help us maintain the ecological balance?

A．By getting illegal practices under control.

B．By stopping us from killing large predators.

C．By bringing the broken-down ecosystems back to normal.

D．By signaling the urgent need for taking preventive action.

4 . I used to be a very self­centered person, but in the past two years I have really changed. I have started to think about other people _______ I think about myself. I am happy that I am becoming a _______ person.

I think my _______ started when I was at Palomar College. At first, I just wanted to get my degree and be left alone. I thought I was smarter than everyone else, so I hardly ever _______ to anyone in my classes. By the end of my first semester, I was really lonely. It seemed as if everyone but me had made friends and was having fun. So I tried a(n) _______. I started asking people around me how they were doing, and if they were having trouble I _______ to help. That was really a big _______ for me. By the end of the year, I had several new friends, and two of them are still my best friends today.

A bigger cause of my new _______, however, came when I took a part­time job at a Vista Nursing Home. One old lady there who had Alzheimer’s disease became my friend. Every time I came into her room, she was so _______ because she thought I was her daughter. Her real daughter never ________ her, so I took her place. She let me ________ that making others feel good made me feel good, too, when she died, I was ________, but I was very grateful to her.

I think I am a much ________ person today than I used to be, and I hope I will not forget these experiences. They have   ________ me to care about other people more than about myself. I ________who I am today, and I could not say that a few years ago.

1.

A．since

B．before

C．or

D．unless

2.

A．famous

B．simple

C．different

D．skilled

3.

A．education

B．career

C．tour

D．change

4.

A．talked

B．wrote

C．lied

D．reported

5.

A．argument

B．game

C．experiment

D．defense

6.

A．dared

B．offered

C．hesitated

D．happened

7.

A．dream

B．problem

C．duty

D．step

8.

A．attitude

B．hobby

C．hope

D．luck

9.

A．polite

B．happy

C．strange

D．confident

10.

A．bothered

B．answered

C．visited

D．trusted

11.

A．explain

B．guess

C．declare

D．see

12.

A．homeless

B．heartbroken

C．bad­tempered

D．hopeless

13.

A．quieter

B．busier

C．better

D．richer

14.

A．forced

B．preferred

C．ordered

D．taught

15.

A．miss

B．like

C．wonder

D．expect

5 . Since the age of three, Chelsie Hill had dreamed of becoming a dancer. “The only thing that I ________ was dance,” she told CBS News. That ________ nearly ended one night. Hill, then a 17-year-old high school senior in Pacific Grove, California, was in a car accident that put her in the hospital for 51 days and left her ________ to move from the waist down. For most people, that would have ________ any hope of a dancing career. ________, for Hill. it was the beginning. ________ being an obstacle, her wheelchair made her more confident. “I wanted to prove to my community — and to myself — that I was still ‘________’,” she told Teen Vogue.

Being normal for her meant dancing, so Hill did it in her wheelchair, which ________ took a lot of learning and patience. After graduation, Hill wanted to expand her dance network to include women like her. She met people online who had the same sufferings and shared her de1termination, and she invited them to dance with her. ________ Hill hoped to reach more people in a larger city, she moved to Los Angeles four years later and ________ a team of dancers with ________, called the Rollettes. “I want to ________ the stereotype of wheelchair users and show that dance is dance, whether you’re walking or you’re ________,” she told CBS News.

Dancing on ________, the Rollettes discovered, can be just as fast-paced and artful as the foot based variety. In disabled dance competitions around the country, the six team members rocked their upper bodies, shook their heads to the beats, and ________ their wheelchairs in energetic and well ________ routines. They’re having fun, and as the audiences’ cheerful ________ indicate, the fun is ________.

Every year Hill holds a dance camp for wheelchair users of all generations and abilities, and last year, 173 ________ from ten countries attended. Hill has ________ what many of us never will: her childhood dream.

1.

A．learnt

B．loved

C．made

D．received

2.

A．impression

B．confusion

C．emotion

D．ambition

3.

A．uneasy

B．unlikely

C．unable

D．unwilling

4.

A．destroyed

B．changed

C．chosen

D．removed

5.

A．Therefore

B．Besides

C．However

D．Moreover

6.

A．Far from

B．But for

C．Far away

D．Except for

7.

A．healthy

B．formal

C．normal

D．friendly

8.

A．averagely

B．occasionally

C．eventually

D．definitely

9.

A．Although

B．Because

C．Once

D．If

10.

A．formed

B．led

C．found

D．represented

11.

A．dreams

B．injuries

C．accidents

D．disabilities

12.

A．break out

B．break down

C．turn out

D．turn down

13.

A．running

B．dancing

C．rolling

D．jumping

14.

A．wheels

B．ground

C．stages

D．feet

15.

A．changed

B．controlled

C．knocked

D．folded

16.

A．required

B．shown

C．designed

D．analyzed

17.

A．movements

B．discussions

C．comments

D．reactions

18.

A．infectious

B．glorious

C．precious

D．harmonious

19.

A．students

B．participants

C．women

D．reporters

20.

A．shared

B．accepted

C．desired

D．achieved

6 . Wherever we go, we are surrounded by history. Across the globe, cultural heritage is passed down through the generations. It is in the buildings and structures around us. It is in the arts and artifacts (手工艺品) we treasure. It lives in the languages we speak and the stories we tell. But today, it is under attack as never before. Not only are the damages of time threatening our cultural heritage, but conflicts, climate change, globalization and tourism are all exacting a heavy price. Technology is now the most essential weapon in the battle. Here’s how technology is preserving our cultural heritage.

As you can imagine, creating the replicas (复制品) via crowd sourced 2D images is extremely time-consuming. Increasingly, artificial intelligence (AI) algorithms (算法) are being used to do all the required sourcing, allowing millions of images to be stored in a matter of hours. AI will also make restoration and preservation of existing cultural heritage far easier and vastly superior to previous methods.

Virtual reality (VR) technology will play a leading role in preserving our cultural heritage in the coming years. Many of the most important sites and architecture are extremely fragile. Human interaction with these locations is doing a great deal of harm. Wastes accumulate everywhere, causing enormous problems. As more cultural heritage sites and objects are digitally mapped and recorded, VR technology will increasingly become the way that people experience them. We’ll all eventually be able to walk through places, look at (and touch!) artifacts and works of art without ever seeing them with our own eyes.

Finally, our cultural heritage will be preserved via technology. Efforts in research, innovation, data sharing and project work will help promote and preserve the cultural heritage of countries all across the world.

1. What does the underlined word “exacting” in paragraph 1 mean?

A．Paying.

B．Cutting.

C．Receiving.

D．Demanding.

2. What is the advantage of AI in preserving cultural heritage?

A．It generates 2D images.	B．It makes restoration easier.
C．It makes preservation safer.	D．It creates replicas in seconds.

3. How does VR help to preserve cultural heritage?

A．By recycling huge amounts of waste.	B．By reducing human impact on the site.
C．By forbidding visitors from touching artifacts.	D．By educating people about the sites’ importance.

4. What is the author’s attitude towards technology application in preserving the cultural heritage?

A．Ignoring.

B．Compromising.

C．Approving.

D．Disagreeing.

8 . Maybe you have heard the expression—when in Rome, do as the Romans do. So when you want to do business in France, you have to get to know French culture, to make marketing plans, and to run your business by local laws.

    1     The French take great pride in their language, so anyone who does not speak it may run the risk of being disrespected by his French colleagues or business partners. Also, another reason why learning French is important is that it is a great way to show every possible French business partner that you care and respect their country's culture and language.

The first thing you should do when meeting someone new is to shake his hand firmly and always look the person in the eye. In social meeting with friends, kissing is common.

Use first names only after being invited to.     2     The French will sometimes introduce themselves using their surname first, followed by their first name.

Dress well.     3     Your business clothing is a reflection of your success and social status. Always try to be tasteful and stylish. Women are advised to dress simply but elegantly. Wearing make-up is practised widely by businesswomen.

The French are passionate about food, so lunches are common in doing business in France, which usually consist of an appetizer (开胃菜), a main meal with wine, cheese, dessert and coffee, and normally take up to two hours.     4    

Do not begin eating until the host says “bon appetite”. Pass dishes to the left, keep wrists above the table and try to eat everything on the plate.     5     This may suggest that you find the food tasteless. If eating in a restaurant, the person who invites always pays.

A．The French draw information about people based on their appearance.

B．This is a time for relationship building.

C．Remember to be as polite as possible.

D．Language should be the focus of anyone planning to do business in France.

E．Be careful with adding salt, pepper or sauces to your food.

F．Use Monsieur or Madame before the surname.

G．Make an appointment with your business partner in advance.

10 . 假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号(∧)，并在其下面写出该加的词。
删除：把多余的词用斜线(\)划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1.每处错误及其修改均仅限一词;
2.只允许修改10处，多者(从第11处起)不计分。

Yesterday I went to see a film call “The Battle at Lake Changjin”. It tells the story to the Chinese People's Volunteer Army taking a part in the war to help Korea fight against the U.S. aggression (侵略). The film was a great successful in the National Holiday period. In the movie, the Chinese army men fought brave below -40℃ in a key battle around Lake Changjin. It was not the film itself that moved people, and the heroes of the war years when fought for our country. The heroes never considered them own safety. Since it was shown, the total box office (票房) reached the top of China's box office. I am looking forward to seeing more wonderful film in the future.