Scientists have created the world's first living, self-healing robots using stem cells (干细胞) from frogs. Named xenobots after the African clawed frog from which they take their stem cells, the ''machines'' are less than a millimeter wide — small enough to travel inside human bodies. They can walk and swim, survive for weeks without food, and work together in groups. ''These are entirely new life forms, '' said the University of Vermont, which conducted the research with Tufts University's Allen Discovery Center.
The researchers removed living stem cells from frog embryos (胚胎), and left them to hatch. Then, the cells were cut and reshaped into specific ''body forms'' designed by a supercomputer — forms ''never seen in nature''，according to a news release from the University of Vermont.
Xenobots even have regenerative abilities. When the scientists sliced into one robot, it healed by itself and kept moving. They don’t look like traditional robots - they have no shiny clothing or robotic arms. Instead, they look more like a tiny drop of moving pink flesh. The researchers say this is deliberate — this ''biological machine'' can achieve things typical robots of steel and plastic cannot. ''Traditional robots degrade over time and can produce harmful ecological and health side effects, '' researchers said in the study. ''As biological machines, xenobots are more environmentally friendly and safer for human health.''
According to the researchers, these robots could be used to clean up radioactive waste, collect microplastics in the oceans, or even carry medicine inside human bodies. Aside from these immediate practical tasks, they could also help researchers to learn more about cell biology - opening the doors to future advancement in human health and longevity. This sounds like something from a sci-fi movie. Some people even voiced their concern that humans might be taken control of by those xenobots. However, the researchers in the study say there is no need for alarm. They can't reproduce or evolve (进化).
1.What is this passage mainly about?
A.The advantages of a medical robot.
B.The application of robots in biology.
C.The general introduction of a living robot.
D.The medical value of African clawed frogs.
2.The underlined word ''regenerative'' in Paragraph 3 probably means ''________''.
A.living longer B.growing again
C.replacing old cells D.defending against attacks
3.What can we know about xenobots?
A.They can do everything that traditional robots can.
B.They can break up steel and plastic while degrading.
C.They are able to cure people of all kinds of diseases.
D.They are harmless to the environment and human health.
4.What is the researchers' attitude to the development of xenobots?
A.Doubtful. B.Positive.
C.Cautious. D.Casual.
Harper Lee was an American novelist widely known for To Kill a Mockingbird, published in 1960, which won the 1961 Pulitzer Prize and has become a classic of modern American literature. The 1962 film adaptation starring Gregory Peck won three Academy Awards.
For decades, the book was Lee’s only major work of published fiction, but it was hugely influential for generations of US readers. It has sold more than 10 million copies, and is one of the most widely taught novels in the US schools. In 2007 she was awarded the Presidential Medal of Freedom for her contributions to literature.
Lee wanted to live a simple life and was never comfortable with the attention the novel won her, and she practically disappeared from public life after it appeared. The world, however, continued waiting for a new novel from her, and on occasion she suggested that she had a story in progress.
In 2015, a book did come out. Go Set a Watchman was more of a first draft, featuring Scout, the young girl who was the main character of To Kill a Mockingbird. Go Set a Watchman tells a story of Scout as an adult. Accusations arose that the 89-year-old Lee was not able to agree to the manuscript’s release，and that various parties had signed on her behalf.
Though Lee moved to New York in 1949, she spent many years guarding her privacy (隐私) in Monroeville, which served as the clear inspiration for the setting in To Kill a Mockingbird.
In 2007, Lee suffered a stroke (中风), but recovered and later settled in Monroeville permanently to care for her sister, Alice, who died in 2014. She was said to eat breakfast every morning at the same fast-food spot, and was friendly with her neighbors. The countless Americans knew her only through her works，and they will undoubtedly miss her.
1.What can be learned about Harper Lee from the first two paragraphs?
A.She was regarded the greatest writer in America.
B.She made great contributions to American literature.
C.She once starred in a film adapted from her own novel.
D.She got her novels well accepted in most American schools.
2.Why did Harper Lee disappear from public life after her first novel came out?
A.She tried to get out of accusations.
B.She wanted to write another novel.
C.She intended to avoid being bothered.
D.She wasn’t comfortable with her novel’s influence.
3.What can we learn about Harper Lee’s Go Set a Watchman?
A.It tells her own life story.
B.It is adapted into a famous film.
C.It won her lots of honors and awards.
D.It continues the story of her earlier one.
4.What can be inferred about Harper Lee from the last paragraph?
A.She died of a stroke in 2014.
B.She will be remembered forever.
C.She cared much for her neighbors.
D.She led a lonely life in her later life.
It's time for fun outside! Take your bathing suit and sunscreen and head to these sunny spots that offer the best getaways for every interest!
San Juan, Puerto Rico
Head to the hot city nightlife of San Juan. Top chefs, stylish hotels, bars, clubs and shops are all just steps away from the tropical beaches. And since Puerto Rico is a United States Commonwealth, it's one of the easiest islands in the Caribbean to visit since you won't need a passport, have to change money, or even worry about your cellphone working. Puerto Rico is also one of the best tropical vacations you can take without leaving the United States.
Riviera Maya, Mexico
What's better than diving into the salty sea? Going into the clear and salt-free waters of the naturally occurring limestone cenotes (石灰岩沼穴) of the Riviera Maya and Yucatan Peninsula. Spend a sunny day exploring these natural cave pools filled with cool water that springs from the ground below and the thick palm forests that surround them. Then head back to the perfectly located Fairmont Mayakoba for comfortable rooms and modem Mexican cuisine.
New Orleans, Louisiana
New Orleans' lively nightlife and live-music scenes make ''the Big Easy'' a great girls' getaway. And even if your crew isn't one to seek out the boozy Bourbon Street crawl, there's plenty of amazing food in the French Quarter，plenty of shopping and strolling in the Garden District.
Clearwater, Florida
If you want to meet a real movie star while also enjoying the sunbath, head to the Gulf shores of Clearwater, Florida. Here you can meet the stars of Dolphin Tale and Dolphin Tale 2, Winter and Hope, who are in residence full-time at the Clearwater Marine Aquarium.
1.What makes Puerto Rico an easy tourist spot to visit?
A.It lies in the Caribbean. B.No passport is needed.
C.It’s near the tropical beaches. D.Many travel services are offered.
2.What can you do if you travel to Riviera Maya?
A.Taste various foods. B.Meet some famous stars.
C.Dive into the salty waters. D.Explore natural cave pools.
3.Which place will you choose if you are a film fan?
A.Clearwater, Florida. B.Riviera Maya, Mexico.
C.San Juan, Puerto Rico. D.New Orleans, Louisiana.
假定你是李华，最近获悉你的美国网友Peter家乡受到飓风(hurricane)侵袭，损失惨重。请你用英语给Peter写一封慰问信。信的内容包括：
1. 得知情况及感受；
2. 表达安慰和鼓励；
3. 打算提供的帮助。
注意：1. 词数100左右；
2. 可以适当增加细节，以使行文连贯.
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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处错误，每句话中最多有两处。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）不计分。
Dear Chris,
I’m sorry to hear that you have been in hospital for several day. Actually, it’s very easily for a person like you to get sick, since you aren’t used to the new environment. Even worst, you don’t take enough exercise. Here are some tips for you：
First of all, it’s good idea to take part in some social activities, that will help you learn more about the local customs and cultures. On addition, you should try hardly to reduce the pressure of work by listening to music and making friends. Last but not least, you’d better to exercise more instead of sit in the office all the time.
I hope that my advice will help you lead a healthy lifestyle and we will recover soon.
Yours Truly,
Li Hua
I started serving the homeless when I was eight years old. I didn't know these people would make such a big difference in my _______.
Twice a month I go to the church and help get things ready for _______. When the gate is opened, people come in _______ to get drinks. They take their seats while breakfast is _______， and then we begin to _______. We each take two plates and carry them _______ the line as the plates are _______. Each person receives several kinds of foods. I walk to the tables and _______ the plates before them. After I've served them, I ask if they need _______ else and bring them whatever they ask for.
When I first started serving, I was a little ________ . At first I stayed close to my mom most of the time, but after I got to know these strangers, I ________ that they were friendly people. And the ________ of them was often nicer than the outside. I realized that there was no ________ to be scared. After serving for a few months, I started to ________ seeing the same people each week.
All of these people make my day much ________. The past two years have made a big ________ in my life. I do this ________ it is the right thing to do. When I serve people, I want them to know that someone ________ them and that they matter. Serving makes me happy, but even more ________， it teaches me to love and ________ others and helps make the world a better place.
1.A.study B.work C.family D.life
2.A.breakfast B.brunch C.lunch D.dinner
3.A.secretly B.quickly C.slowly D.separately
4.A.ordered B.enjoyed C.prepared D.tasted
5.A.eat B.serve C.leave D.try
6.A.before B.beyond C.above D.along
7.A.emptied B.washed C.filled D.dried
8.A.make B.set C.fix D.show
9.A.nothing B.everything C.what D.anything
10.A.surprised B.embarrassed C.scared D.puzzled
11.A.realized B.admitted C.claimed D.swore
12.A.past B.inside C.surface D.front
13.A.way B.doubt C.reason D.wonder
14.A.get tired of B.take charge of C.get down to D.look forward to
15.A.better B.further C.busier D.easier
16.A.success B.difference C.profit D.fortune
17.A.because B.if C.once D.though
18.A.relies on B.goes after C.cares about D.looks for
19.A.necessarily B.interestingly C.honestly D.importantly
20.A.respect B.forgive C.inspire D.protect
