1 . While some allergies (过敏症) disappear over time or with treatment, others last a lifetime. For decades, scientists have been searching for the source of these lifetime allergies.

Recently, researchers found that memory B cells may be involved. These cells produce a different class of antibodies known as IgG, which ward off viral infections. But no one had identified exactly which of those cells were recalling allergens or how they switched to making the IgE antibodies responsible for allergies. To uncover the mysterious cells, two research teams took a deep dive into the immune (免疫的) cells of people with allergies and some without.

Immunologist Joshua Koenig and colleagues examined more than 90, 000 memory B cells from six people with birch allergies, four people allergic to dust mites and five people with no allergies. Using a technique called RNA sequencing, the team identified specific memory B cells, which they named MBC2s that make antibodies and proteins associated with the immune response that causes allergies.

In another experiment, Koenig and colleagues used a peanut protein to go fishing for memory B cells from people with peanut allergies. The team pulled out the same type of cells found in people with birch and dust mite allergies. In people with peanut allergies, those cells increased in number and produced IgE antibodies as the people started treatment to desensitize them to peanut allergens.

Another group led by Maria Curotto de Lafaille, an immunologist at the Icahn School of Medicine at Mount Sinai in New York City, also found that similar cells were more plentiful in 58 children allergic to peanuts than in 13 kids without allergies. The team found that the cells are ready to switch from making protective IgG antibodies to allergy-causing IgE antibodies. Even before the switch, the cells were making RNA for IgE but didn’t produce the protein. Making that RNA enables the cells to switch the type of antibodies they make when they encounter allergens. The signal to switch partially depends on a protein called JAK, the group discovered. “Stopping JAK from sending the signal could help prevent the memory cells from switching to IgE production,” Lafaille says. She also predicts that allergists may be able to examine aspects of these memory cells to forecast whether a patient's allergy is likely to last or disappear with time or treatment.

“Knowing which population of cells store allergies in long-term memory may eventually help scientists identify other ways to kill the allergy cells,” says Cecilia Berin, an immunologist at Northwestern University Feinberg School of Medicine. “You could potentially get rid of not only your peanut allergy but also all of your allergies.”

1. Why did scientists investigate the immune cells of individuals with and without allergies?

A．To explore the distinctions between IgG and IgE.

B．To uncover new antibodies known as IgG and IgE.

C．To identify cells responsible for defending against allergies.

D．To reveal cells associated with the development of allergies.

2. What does the word “desensitize” underlined in Paragraph 4 most probably mean?

A．Make. . . less destructive.	B．Make. . . less responsive.
C．Make. . . less protective.	D．Make. . . less effective.

3. What can we learn from the two research teams’ work?

A．MBC2s make antibodies and proteins that prevent allergies.

B．Memory B cells generate both RNA for IgE and the corresponding protein.

C．JAK plays a role in controlling antibody production when exposed to allergens.

D．Allergists are capable of predicting whether an allergy will last or disappear.

4. Which could be the best title for the passage?

A．RNA Sequencing Is Applied in Immunology Research

B．Specific Cells Related to Peanut Allergies Are Identified

C．Unmasking Cells’ Identities Helps Diagnose and Treat Allergies

D．Newfound Immune Cells Are Responsible for Long-lasting Allergies

2 . As this year draws to a close, I still remember the fear I felt on a bright Saturday morning in late September, at a five-kilometer race in Clarkston, Georgia, as I waited for my 11-year-old son at the finish line.

I knew he could run a 5k in about 30 minutes. When I didn't see him at the 35-minute mark, I began to wonder what had gone wrong. Had he gotten lost? Was he hit by a car? About an hour earlier, when we drove into town, my son noticed an insect on my car. It was bright green, no longer than a fingernail. And it was friendly. This little green thing hopped onto my son's finger, where it stayed for a long, long time. It stayed so long that we eventually gave it a name: Little Friend.

A few minutes before the race, Little Friend jumped off my son’s hand and landed on the sidewalk. But pedestrian traffic was heavy and unpredictable. Little Friend was in danger. So my son knelt and reached out his hand. Little Friend came back.

The race was about to start, and the tiny green insect was in for a wild ride. My son would run fast, and the race would be long, and his arms would swing, and Little Friend would eventually be shaken off.

“You will lose Little Friend,” I told him.

My son nodded, treating the moment with appropriate seriousness.

The race began, and I lost sight of him.

The excitement at the finish line gave way to anxiety when my son did not show up.

I kept asking people if they'd seen him. No one had. And beyond the 40-minute mark, I was in a panic.

But there he was, thank goodness, just ahead of the 45-minute mark.

And there was Little Friend, riding on the upper crook of his right thumb like a very small captain on a very tall ship.

My predictions had been wrong. My son had not run fast, and he had not lost Little Friend. And these two facts seemed somehow related. He blamed a cold he was getting over. I suspected it was more than that, but I didn’t question him too much about it.

We walked back to the car, smiling, and found some bushes in the parking lot that seemed like a good place for my son to drop off Little Friend.

“Be free,” my son said, and gently put it in the bushes.

My son knew the truth. Sometimes life gives you something beautiful, a fragile, short-lived treasure in your hand. There is no need to rush ahead. Treat it gently. Enjoy each moment. Hold on while you can.

One day my son will leave too, running off on his own adventure.

1. How did the writer probably feel when he finally saw his son appear in sight?

A．Relieved.

B．Depressed.

C．Satisfied.

D．Disappointed.

2. The son failed to run as fast as his father had expected probably because ________.

A．he was lost	B．he was recovering from a cold
C．he was afraid to lose the tiny insect	D．he was slowed down by the heavy traffic

3. As for the way his son treated Little Friend, the writer is ________.

A．indifferent

B．anxious

C．appreciative

D．doubtful

4. What will the writer most probably do after the race?

A．Treasure every moment he has with his son.

B．Encourage his son to take more adventures.

C．Tell his son to take races seriously.

D．Get more insects for his son.

3 . 语法填空

The 5-Second Rule suggests food is OK to eat if you pick it up     1    five seconds or less. Believe it or not, scientists have tested the rule. We’re sorry to report it’s not necessarily true. Bacteria can attach     2     (it) to your food instantly, regardless of how quickly it     3     (pick) up. Food left there for five seconds or less will probably collect less bacteria than food sitting there for a longer time, but fast may not be fast enough. Floors, even clean-looking ones, harbor bacteria. Ultimately, if in doubt, abandon the food     4     (avoid) potential illness.

4 . 阅读下列短文，根据短文内容填空。在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

Parents often believe that they have a good relationship with their teenagers. But last summer, Joanna and her husband noticed a change in their older son: Suddenly, he seemed to be talking far more to his friends     1     to his parents. “Usually, the door to his room     2     (shut).” Joanna noted.

5 . 阅读下列短文，根据短文内容或括号内所给词的恰当形式填空。

Some students are     1     (amuse) by something else. They spend all their time     2     (look) anywhere but at me. Then again, some students’ favorite activity is daydreaming. With their chins on their hands, they occupy     3     (they) by staring out of the window or up at the ceiling. They are certainly interested in something, but who knows what. The main thing is reminding distracted students that they need to pay attention in class.

6 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Recently, you may have noticed some new trends in the fashion industry, from “dopamine (多巴胺) dressing” to “tomato girl”. Now, it is the perfect time     1     (try) something new with the “Maillard style” that’s getting popular on social media.

The term “Maillard” originally refers to the Maillard     2     (react). This phenomenon is well-known in Western cuisine. It describes a chemical change that produces flavor chemicals and browning in foods such as toast and steak, as     3     (note) by BBC Science Focus.

    4     (similar), Maillard-inspired fashion creates clothes     5     show different kinds of brown, like rich reddish-browns, warm yellow-browns, and delicate off-whites(米色). This makes     6     easier for people to think of the rich tastes food brings,     7     (create) pleasant emotions in their brains.

    8     (compare) to the bright colors of “dopamine dressing” and the fresh “tomato girl” look, the dark earth colors that Maillard style uses reflect the autumn season and give people a     9     (comfort) feeling.

The style has also become     10     hit among many famous brands. At fashion shows showing off their new autumn products, brands like Miu Miu, Hermes, and Miuccia Prada have all presented Mailard-themed clothes one after another.

7 . Beyond the classroom, the US provides various job opportunities that allow students to gain practical experience, earn income and enhance their skill sets. Here are some of the diverse employment avenues available for international students while attending university in the US.

On-campus employment

Many US universities offer on-campus employment opportunities for international students, providing a convenient and accessible way to earn income while pursuing their studies. These positions may include roles in libraries, administrative offices, student centers, or even research assistantships within academic departments. On-campus employment is typically limited to 20 hours per week during the academic year, allowing students to balance work and study commitments.

Off-campus employment

Off-campus employment opportunities are also available, although with certain restrictions. The two primary categories of off-campus employment are optional practical training (OPT)and curricular practical training (CPT). OPT allows students to work in their field of study for up to 12 months (or 24 months for STEM fields)after graduation, providing valuable real-world experience. CPT, on the other hand, permits students to engage in practical training directly related to their academic program while still attending their university.

Internships and cooperative programs

Many US universities have robust internship and cooperative education programs that connect students with industry partners. These programs offer international students the chance to apply classroom knowledge in professional settings, fostering skill development and industry connections. Internships, whether paid or unpaid, are valuable stepping stones that often lead to full-time employment opportunities after graduation.

Research assistantships

For students pursuing advanced degrees, research assistantships provide a unique opportunity to work closely with faculty on cutting-edge research projects. These positions not only contribute to academic and professional growth but also offer financial backing. Research assistantships can be found in various disciplines, including science, engineering, social sciences and humanities.

1. What sets On-campus employment apart from other job opportunities?

A．It is available before graduation.

B．Its work time is no more than 20 hours every week.

C．It can help students earn money and pursue their studies.

D．It provides cutting-edge research projects.

2. Which of the following can pave the way for students’ full-time employment?

A．On-campus employment.	B．Off-campus employment.
C．Internships.	D．Cooperative programs.

3. What can Research assistantships provide for international students?

A．A university degree.	B．Industry connection.
C．Real-world experience.	D．Financial support.

8 . Not many drinks can offer the health benefits of tea, the strength of coffee, and the joy of chocolate like this super brew, yerba mate. Along with supposed benefits of supporting weight loss, concentration, and better digestion, drinking yerba mate continues to symbolize culture and tradition in South America.

Consumed mostly in Argentina, Uruguay, Paraguay and Brazil — as well as in Syria and Lebanon — yerba mate (pronounced MAH-tay)is a hot, bitter, caffeinated tea made by steeping the dried leaves of the yerba mate plant. Containing roughly as much caffeine as coffee, about 80 milligrams per cup, mate has gained global popularity — much so that brands like Perrier, Red Bull, and PepsiCo have launched mate drinks.

But in the last couple of decades, mate started experiencing a boom outside of South America. Karla Johan, a mate sommelier (侍酒师) from Argentina, attributes this partly to football players from Argentina and Uruguay bringing the habit to Europe, where they moved to play for local teams. In fact, one might say that mate is the “beverage of champions”. When Argentina’s national football team travelled to Qatar in December 2022 to play and won the World Cup, they carried 240 kg of yerba mate with them.

Yerba mate, of course, eventually migrated over to the U. S. and in recent years has become a popular ingredient in everything from health elixirs (保健药) to energy drinks. Loose leaves can be purchased at most specialty grocery stores to make the drink at home. And if you want to get the full yerba mate experience, you can even order a cup for drinking mate and bombilla online, gather some friends, and enjoy the beauty of the South American ritual for yourself.

Global messaging platform WhatsApp recently introduced a mate emoji, which points to mate’s growing popularity as people aim for a healthier lifestyle. That’s because mate, said Johan, contains a higher level of antioxidants than green tea or red wine, and a powerful combination of vitamins from the clay soil where it grows. In Argentina, mate is common, a faithful companion for matters great and small. Yet, unlike coffee or tea, it is not consumed in cafes: It’s what you have at home and at work, in the park and on the train, during class or at the gym.

1. Which of the following is not the feature of yerba mate?

A．Its bitter flavor.	B．Its long history.
C．Its ingredient of caffeine.	D．Its function of losing weight.

2. What makes yerba mate globally popular?

A．Its unique coffee taste.

B．Its health benefits.

C．The support of famous football players.

D．The launch of mate drinks by famous brands.

3. Which is the following is NOT true about yerba mate according to paragraph 4?

A．It can be easily accessible.	B．It can cure some diseases.
C．It can be made into energy drinks.	D．It can be purchased online.

4. Why do people show preference for yerba mate according to paragraph 5?

A．Because it is a faithful companion.

B．Because it can be enjoyed everywhere.

C．Because it contains some beneficial elements.

D．Because it is better than green tea and red wine.

9 . 在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

Sue took some paper and a pen into Johnsy’s room and began a pen drawing, in an attempt     1     (raise) Johnsy’s spirits. Johnsy’s eyes were open, but they weren’t watching her. Instead, she stared     2     the window and     3     (count) backwards: “Ten, nine, eight, seven...”

“What are you counting, dear?” asked Sue. “They     4     (fall) faster now,” replied Johnsy. “Three days ago there were almost a hundred. But now it’s easy. There are only five left now. Five leaves on the ivy vine. When the last one falls, I must go, too. Didn’t the doctor tell you?”

10 . 在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

Jobs and occupations come and go at an     1     (amaze) pace these days. If you think you can’t be replaced by software, or your job can’t be outsourced to some robots on the moon, you are wrong. What if your job disappears after working for 10 years in the field? You may have to go back to the classroom and     2     (retrain) in order to qualify to work in another field. In fact, in all likelihood, you will have to do this multiple times. But you can be prepared for developments and changes before you are thrown out of a career. It is     3     (entire) your choice to learn, or to be forced to learn.