5 . An experimental treatment rejuvenates (使...恢复活力) the immune (免疫的) systems of older mice, improving their ability to fight infections. If it works in humans, the treatment could reverse (逆转) age-related decreases in immunity that leave older adults susceptible to disease.

These decreases may be due to changes in our blood stem cells which can develop into any type of blood cell—including key parts that make up the immune system. As we age, a larger proportion (比例) of these stem cells tend to produce some immune cells over others, says Jason Ross at Stanford University in California. This imbalance damages the immune system’s defenses.

Ross and his colleagues have developed a treatment using antibodies (抗体), which are proteins that recognize and attack certain cells to target these abnormal stem cells. They tested the treatment in six mice between 18 and 24 months old, which is roughly equal to an age of 56 to 70 years in humans.

A week after receiving an antibody injection, the mice had about 38 percent fewer of these abnormal stem cells than six mice of the same age that didn’t receive the treatment. “You can think of it as kind of turning back the clock,” says Ross. “We’re making the proportion of these immune cells more similar to those of a younger adult mouse.”

To test if the changes resulted in a stronger immune system, the researchers vaccinated (打疫苗) 17 older mice against a mouse virus. Nine of these mice had received the antibody treatment eight weeks earlier. The researchers then infected (感染) the mice with the virus. Two weeks later, they measured the number of infected cells in the animals and found that nearly half of the treated mice had cleared the infection, compared with only one of the eight untreated mice.

The findings indicate that the antibody treatment rejuvenates the mouse immune system. “Since humans, like mice, also see abnormal blood stem cells increase with age, a similar antibody treatment may rejuvenate our immune systems,” says Ross.

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

A．Strongly resist.	B．Easily suffer from.
C．Completely unaffected by.	D．Highly immune to.

2. What may cause age-related decreases in immunity?

A．Changes in our nervous system.

B．An increase in antibodies in our body.

C．Changes in blood stem cells.

D．A decrease in the number of immune cells.

3. How did the researchers measure the effectiveness of the antibody treatment on the mice?

A．By analyzing changes in their lifestyle.

B．By observing differences in their behavior.

C．By conducting blood tests to measure immune cell counts.

D．By counting the number of infected cells after virus contact.

4. What conclusion can be drawn from the findings of the study?

A．The antibody treatment has no effect on the mouse immune system.

B．The antibody treatment increases the risk of infections in mice.

C．The antibody treatment only works on young mice, not older ones.

D．The antibody treatment improves the mouse immune system.

6 . “Have you ever considered giving up during a race?” a runner asked me during the Geneva Marathon. We’d _________ and keeping going felt like walking through a marsh (沼泽). Even the appealing scenery along the way wasn’t enough to _________ our spirits.

“I can’t think of a single race when I haven’t!” I answered _________. The runner beside me looked a little relived. Encouraged, I went on to _________ a few of the weak moments I’d overcome to persuade her to _________. My biggest _________ came during the first half of the 56-mile Marathon in South Africa, I told her. Running it was a _________ dream, but when I found myself on a steep hill with painful blisters (水疱) between my toes after a(n) _________ decision to wear no socks.

“If I give up now, I’ll _________ myself six hours of pain,” I continued. In that moment, 1,000 km of __________ training and the thousands of pounds I’d spent on flights and accommodation didn’t __________ at all.

__________, someone at my running club had laughed at the idea of a slow runner like me entering the marathon like this, and recalling this inspired me to keep moving.

“I may not finish this race before the 12-hour __________, but I’m not going to give that man the chance to say, “I told you so”, I said. Soon afterwards, I buddied up with another __________, a six-hour chat __________ and we got each other to the finish with 17 minutes to spare.

1.

A．gone away

B．fallen behind

C．taken off

D．come back

2.

A．lift

B．break

C．lower

D．feel

3.

A．confidently

B．proudly

C．honestly

D．rudely

4.

A．seize

B．relate

C．make

D．copy

5.

A．stop

B．rise

C．continue

D．quit

6.

A．opportunity

B．mistake

C．practice

D．test

7.

A．lifelong

B．forgotten

C．distant

D．disappointing

8.

A．thoughtful

B．unwise

C．careful

D．difficult

9.

A．leave

B．get

C．spare

D．offer

10.

A．simple

B．relaxing

C．enjoyable

D．tiring

11.

A．work

B．matter

C．appear

D．exist

12.

A．Fortunately

B．Surprisingly

C．Regrettably

D．Undoubtedly

13.

A．headline

B．limit

C．journey

D．work

14.

A．runner

B．judge

C．worker

D．student

15.

A．concluded

B．interrupted

C．failed

D．followed

7 . Natasha Tucker’s passion for fighting plastic pollution began with a shocking moment.

While working at the Vancouver Aquarium, Tucker met a rescued dolphin whose fins were partially cut off due to fishing equipment entanglement (缠绕). This heartbreaking experience made Tucker immediately search for a way to take action against the plastic pollution that caused these injuries.

“I saw immediately that this was because of us,” she says. “I knew I had to do something. Then, I found Mind Your Plastic.”

That aquarium encounter was not the only experience that inspired Tucker to action. Other experiences like working in retail management came with witnessing tons of plastic waste. “I saw how much got thrown out, and it didn’t sit well with me,” she says.

Plastic waste in business is among what Mind Your Plastic is seeking to end via its three key programs: the Circular Economy Ambassador Program(CEAP) for educators and youth, the Plastic-Free Events Policy Program for municipalities (市政当局) and the Plastic Awareness and Reduction Tool-kit s (PART) Program for businesses.

When people donate to Mind Your Plastic, their dollars directly support these programs and help them effect change. Through direct partnerships with local educators, municipalities and businesses, these programs connect Canadians with direct ways to take action. The CEAP program, for example, helps teachers educate youth about the circular economy, lead local cleanups, and track collected waste.

The blame game is another area in need of transition, according to Tucker, who says that big companies, not customers, should carry the responsibility to solve Canada’s plastic pollution problem.

“It’s felt for a long time like the responsibility is placed on the customers,” says Tucker. “That needs to stop.”

Tucker says this perspective (观点) can be shifted by individuals creating public pressures—for example, pushing for policy—and using their dollars to support more sustainable, circular alternatives until these policy changes happen.

“This makes policy a valuable tool. And big business may say there’s no interest, but we know there is,” she says. “Let’s use our dollars to prove that, and challenge policymakers to help make change happen.”

1. What first inspired Natasha Tucker’s passion for fighting plastic pollution?

A．Working in retail management.	B．Witnessing tons of plastic waste.
C．Meeting an injured dolphin.	D．Finding Mind Your Plastic.

2. What does the underlined sentence in paragraph 4 mean?

A．Tucker felt uneasy about the large quantity of the plastic.

B．Tucker was unconcerned about the amount of plastic waste she saw.

C．Tucker enjoyed managing so much plastic waste.

D．Tucker thought the amount of plastic waste was acceptable.

3. According to the text, how does Mind Your Plastic aim to effect change?

A．By blaming consumers for plastic waste.	B．By providing education and partnership.
C．By quarreling with big businesses.	D．By stop ping using plastic products.

4. What is the passage mainly about?

A．The harmful effects of plastic pollution on life in the ocean.

B．Natasha Tucker’s personal experiences and her fight against plastic pollution.

C．The programs of Mind Your Plastic to reduce plastic waste.

D．The responsibility of big companies in solving Canada’s plastic pollution problem.

8 . It’s not hard to see how welcoming Berlin is to families. There are kid-orientated (儿童导向的) cafes and imaginatively themed playgrounds. Parks and woodlands provide plentiful picnicking opportunities and, in hot weather, lakes offer sunbathing.

Getting around is easy, too. The city’s neighborhoods are walkable, and its public transport network efficient and cheap. Its wide, flat streets, bike lanes and family-friendly cycle hire make two wheels a great way to explore while taking in the city's impressive sights—all of which make Berlin a memorable family destination.

What to do with toddlers (学步的儿童)

A popular neighbourhood with families, Prenzlauer Berg has playgrounds, parks and pretty streets with shops selling kids’ clothes and toys, as well as family-friendly cafes. For those gifted in music, the Frank Gehry-designed concert hall at the Barenboim-Said Academy hosts morning concerts for babies under 12 months and afternoon concerts for one-to-five-year-olds. Meanwhile, central Tiergarten is a wonderful spot for walking, picnicking or kicking a ball in the grass; wander through the woods, spotting cultural sights. Of the park’s six playgrounds, the one close to Thomas-Dehler-Strasse is best equipped for toddlers.

What to do with tweens and teenagers

The Deutsches Technik museum will absorb transport and technology fans for hours. For those ready to learn about the darkest chapter of German history, the Topography of Terror museum is located on the site of the former SS and Gestapo (盖世太保) headquarters. Checkpoint Charlie is a few minutes walk away and the Memorial to the Murdered Jews of Europe can be reached in around 20 minutes on foot. To experience a little of Berlin's alternative side, Bearpit Karaoke is held on Sundays at Mauer park.

1. Which of the following is NOT mentioned as a family-friendly activity in Berlin?

A．Visiting kid-oriented cafes.

B．Enjoying concerts at the Barenboim-Said Academy.

C．Shopping for kids’ toys in stores.

D．Swimming and surfing in lakes.

2. Which activity is recommended for families with toddlers in Tiergarten?

A．Visiting museums.	B．Picnicking and walking.
C．Riding bikes.	D．Shopping for toys.

3. For teenagers interested in German history, which place would be most suitable to visit?

A．Deutsches Technik museum	B．Prenzlauer Berg
C．Topography of Terror museum	D．Mauer park

9 . Dogs may understand more than they show. Pet dogs’ brains displayed neural (神经的) signs of surprise when their owners showed them an unexpected toy. The findings, published March 22 in Current Biology, suggest that dogs create mental concepts of objects.

“Anyone who has ever interacted very much with a dog probably is not that surprised to know that dogs understand that your speech is referring to at least a few common objects,” says Ellen Lau, a neuroscientist at the University of Maryland in College Park. But some people may have assumed this “understanding” is a simple reaction to the sound of the word.

Marianna Boros, a neuroscientist at Eotv’s Lorand University in Budapest, recruited 27 pet dogs and their owners. The team asked the owners to bring five familiar toys and other objects to the lab. Researchers stuck electrodes (电极) to the dogs’ heads and gave them two tasks: lieon a mat and stay awake.

Every so often, a dog would hear a recording of its owner saying things like, “Kun-Kun, look, the ball!” The dog’s owner was on the other side of a wall with a window covered by the curtains. Just after the recording played, the curtains were opened, showing the owner holding a toy—the ball or a different toy, such as a rope.

Just after seeing an unexpected object, an electrode monitoring (监测) brain activity picked up a larger-than-normal signal. This signal indicates surprise, the team says, and suggests that the dog had already formed a mental concept and expectation of the ball after hearing that word. In fact, the signal was especially strong for a mismatch involving words that the dogs reportedly knew very well. “That suggests that it is really about understanding and knowledge of the word,” Boros says.

1. Which statement best reflects Ellen Lau’s view on dogs’ understanding of speech?

A．Dogs understand speech primarily as a reaction to the sound of words.

B．Dogs understand speech, especially when it involves common objects.

C．Dogs have limited understanding of speech, mainly reacting to tone.

D．Dogs shows understanding of the deeper meaning of the speech.

2. How did researchers test dogs’ reactions?

A．By monitoring their brain activity.	B．By observing their behaviors.
C．By playing recordings.	D．By opening the curtains.

3. What does the signal mentioned in paragraph 5 indicate?

A．Dogs hear commands.	B．Dogs display behaviors.
C．Dogs show interest.	D．Dogs form expectations.

4. Which might be the best title for the text?

A．Examining Dogs’ Hearing of Words	B．Revealing Dogs’ Mental Concepts
C．Exploring Dogs’ Reactions to the Orders	D．Studying Dogs’ Neural System