30You might think of your teeth as tools, like built-in knives and forks, but if they are mere tools, why do they feel pain and wouldn't it be better if they could just 26 under any condition? In spite of our 27 discomfort, it turns out there's a good reason our teeth are so sensitive. Tooth pain is a 28 mechanism that ensures when a tooth is being damaged we'll notice and do something about it. If we eat something too hot or too cold, or if the tooth is worn down enough where the tissue 29 is exposed, all of those things cause pain, and then the pain causes the person not to use that tooth to try to protect it a little bit more. So it's really a protective mechanism more than anything else. If teeth didn't feel pain, we might 30 to use them in situations that damage them, and for humans, damaging 31 teeth is a problem because, unlike crocodiles, we can't 32 them. Teeth have three layers, only one of which—the innermost layer of the tooth—can hurt, as that layer of the tooth 33 both blood vessels and nerves. Pain is the only feeling to which the nerves in that layer respond. Whereas people with tooth sensitivity may complain, for example, of tooth pain 34 by heat or cold, the nerves in the inner layer don't sense temperature. Rather, they feel pain, which may be 35 with, say, drinking something very cold. A、adultB、associatedC、chewD、containsE、continueF、defenseG、dentalA.downwardB.emotionalC.impliesD.mammalE.replaceF.swallowG.triggeredH.underneath

【题文】Swap, Don’t shop!You keep hearing about recycling, right? But it doesn't end with bottles, cans, and paper. Clothing takes a huge amount of natural resources（资源）to make, and buying loads of new clothing（or throwing out old clothing）is not healthy for the environment. So what to do with all those perfectly-good-but-you're-maybe-a-little-sick-of-them clothes piled on your bedroom floor? 【小题1】. It's the best way to get rid of your used clothes, score clothes from your friends, and have a party all at the same time.A successful swap depends on the selection of clothes, the organization of the event, and, obviously, how much fun is had. It's really easy to do! Here are a few pointers. ●Invite 5—10 people so you have a nice selection. 【小题2】 , and there may not be enough things to choose from; more than that, and it becomes uncontrollable. ●【小题3】. They should also prepare plenty of reusable bags to carry their "new" clothes home. ●Put different types of clothing on different surfaces in the room.【小题4】. Place a few mirrors around your room so people can see how things look when they try them on. One of the ground rules of the swap should be that everyone must try on the clothes before they take them—things always look different when you put them on.●Set a starting time. Maybe you say “go,” or turn on a certain song, or whatever. 【小题5】. And don't forget to put out some cookies and fruits. Remember, it's a party! A．Less people than that B．Hold a clothing swap C．If two people are competing D．Just keep music playing throughout E．Donate whatever clothes are left over F．Have everyone put their clothes in the right spots G．Tell everyone to bring clean clothes in good condition

Diets have changed in China — and so too has its top crop. Since 2011, the country (grow) more corn than rice. Corn production has jumped nearly 125 percent over past 25 years, while rice has increased only 7 percent. A taste for meat is (actual) behind the change: An important part of its corn is used to feed chickens, pigs, and cattle. Another reason for corn's rise: The government encourages farmers to grow corn instead of rice (improve) water quality. Corn uses less water rice and creates less fertilizer (化肥) runoff. This switch has decreased (pollute) in the country's major lakes and reservoirs and made drinking water safer for people. According to the World Bank, China accounts for about 30 percent of total (globe)fertilizer consumption. The Chinese Ministry of Agriculture finds that between 2005 — when the government (start) a soil-testing program gives specific fertilizer recommendations to farmers — and 2011, fertilizer use dropped by 7.7 million tons. That prevented the emission (排放) of 51.8 million tons of carbon dioxide. China's approach to protecting its environment while (feed) its citizens "offers useful lessons for agriculture and food policymakers worldwide." says the bank's Juergen Voegele.

Online classes began to be popularized just a few decades ago.They are advertised as a way for adults to finish their education and students to learn the material at their own pace—it is far more suitable for people with busy schedules. But after being enrolled in an online course last fall semester，I came to realize online classes were merely a means to fulfil course requirements. First of all，students lack the desire to learn，and they simply complete their assignments to receive credit for a passing grade rather than genuinely engage with the course material. As online courses tend to have more than 100 students，most of the assignments are short and simple.They are not designed for students to interact with the material in depth but designed to be graded easily to accommodate such a large number of students. Perhaps the biggest disadvantage of taking an online class is the absence of face-to-face interaction between the teacher and their students.Live sessions are infrequent and are often scheduled during the middle of the day when students have to attend other classes or work.The office hours of the professor may also be during inconvenient times for many students as well.Most interaction with the professor has to be through email which is often impersonal.It is nearly impossible for students to build a relationship with their professor. There is also little interaction among students.It can be harder for students to create study groups and form relationships with their peers. Online classes also require either a computer or laptop and a reliable Internet connection.Not all students have access to these types of resources，whether it is for financial or other reasons，and some students can be put at a disadvantage.Offering online classes certainly helps students who would otherwise not be able to attend classroom sessions.However，they fail to provide a true education with an emphasis on convenience rather than critical thinking.We need restructure online classes in which students can have a learning experience that will actually provide quality education.（1）What can we infer about students enrolled in online classes？ ____ A.They are unmotivated to learn，B.They can access course materials easily.C.They rarely fulfil the course requirements.D.They can learn at their own pace.（2）What is the author's opinion about online course assignments？ ____ A.They are meant to facilitate interaction.B.They are made convenient to mark.C.They are given to accommodate students' needs.D.They are based on easily accessible material.（3）From the passage，which is one disadvantage of online classes？ ____ A.They make professors' offices much less accessible.B.They are frequently scheduled at irregular times.C.They provide little chance for students to build relationships with each other.D.They tend to increase professors' burden of replying students' emails.（4）What problem may arise if classes go online？ ____ A.Teachers will worry about poor Internet connections.B.Most students may get critical thinking skills from it.C.Schools with limited resources will be at a disadvantage.D.Some students may have difficulty attending them.

A: Jenny, I heard you’ve been promoted.B: Oh yes. It’s such a happy _________ .A: Well, ______________ to you! You’ve worked so hard these past years and you ________ it. I’m so happy for you.B: Thank you, David.

Diets have changed in China – and so too has its top crop. Since 2011, the country (1) (grow) more corn than rice. Corn production has jumped nearly 125 percent over (2) past 25 years, while rice has increased only 7 percent. A taste for meat is (3) (actual) behind the change: An important part of its corn is used to feed chickens, pigs, and cattle. Another reason for corn’s rise: The government encourages farmers to grow corn instead of rice (4) (improve) water quality. Corn uses less water (5) rice and creates less fertilizer (化肥) runoff. This switch has decreased (6) (pollute) in the country’s major lakes and reservoirs and made drinking water safer for people. According to the World Bank, China accounts for about 30 percent of total (7) (globe) fertilizer consumption. The Chinese Ministry of Agriculture finds that between 2005 – when the government (8) (start) a soil-testing program (9) gives specific fertilizer recommendations to farmers – and 2011, fertilizer use dropped by 7.7 million tons. That prevented the emission (排放) of 51.8 million tons of carbon dioxide. China’s approach to protecting its environment while (10) (feed) its citizens “offers useful lessons for agriculture and food policymakers worldwide,” says the bank’s Juergen Voegele. (1) __________ (2) __________ (3) __________ (4) __________ (5) __________ (6) __________ (7) __________ (8) __________ (9) __________ (10) __________

In the classic marriage vow（誓约）, couples promise to stay together in sickness and in health. But a new study finds that the risk of divorce among older couples rises when the wife—not the husband—becomes seriously ill."Married women diagnosed with a serious health condition may find themselves struggling with the impact of their disease while also experiencing the stress of divorce, " said researcher Amelia Karraker.Karraker and co-author Kenzie Latham analyzed 20 years of data on 2, 717 marriages from a study conducted by Indiana University since 1992. At the time of the first interview, at least one of the partners was over the age of 50.The researchers examined how the onset（发生） of four serious physical illnesses affected marriages. They found that, overall, 31% of marriages ended in divorce over the period studied. The incidence of new chronic（慢性的） illness onset increased over time as well, with more husbands than wives developing serious health problems."We found that women are doubly vulnerable to marital break-up in the face of illness, " Karraker said, "They're more likely to be widowed, and if they're the ones who become ill, they're more likely to get divorced."While the study didn't assess why divorce is more likely when wives but not husbands become seriously ill. Karraker offers a few possible reasons. "Gender norms and social expectations about caregiving may make it more difficult for men to provide care to sick spouses（配偶）, " Karraker said. "And because of the imbalance in marriage markets, especially in older ages, divorced men have more choices among prospective partners than divorced women."Given the increasing concern about health care costs for the aging population, Karraker believes policymakers should be aware of the relationship between disease and risk of divorce."Offering support services to spouses caring for their other halves may reduce marital stress and prevent divorce at older ages." she said. "But it's also important to recognize that the pressure to divorce may be health-related and that sick ex-wives may need additional care and services to prevent worsening health and increased health costs."What can we learn about marriage vows from the passage? A.They are as binding as they used to be.B.They are not taken seriously any more.C.They may not guarantee a lasting marriage.D.They may help couples tide over hard times.What did Karraker and co-author Kenzie Latham find about elderly husbands? A.They are generally not good at taking care of themselves.B.They are more likely to infect serious illnesses than their wives.C.They can develop different kinds of illnesses just like their wives.D.They can become increasingly vulnerable to serious illnesses.Why is it more difficult for men to take care of their sick spouses according to Karraker? A.They expect society to do more of the job.B.They find it more important to make money for the family.C.They think it more urgent to fulfill their social obligations.D.They are more accustomed to receiving care.What does Karraker think is also important? A.Providing extra care for divorced women.B.Stabilizing old couples' relations.C.Making men pay for their wives' health costs.D.Reducing marital stress on wives.

According to a review of evidence in a medical journal, runners live three years (1) (long) than non-runners. You don’t have to run fast or for long (2) (see) the benefit. You may drink, smoke, be overweight and still reduce your risk of (3) (die) early by running. While running regularly can’t make you live forever, the review says it (4) (be) more effective at lengthening life (5)walking, cycling or swimming. Two of the authors of the review also made a study published in 2014 (6) showed a mere five to 10 minutes a day of running reduced the risk of heart disease and early deaths from all (7) (cause). The best exercise is one that you enjoy and will do. But otherwise ... it’s probably running. To avoid knee pain, you can run on soft surfaces, do exercises to (8) (strength) your leg muscles (肌肉), avoid hills and get good running shoes. Running is cheap, easy and it’s always (9) (energy). If you are time poor, you need run for only half the time to get the same benefits as other sports, so perhaps we should all give (10) a try. (1)_______________ (2)_______________ (3)_______________ (4)_______________ (5)_______________ (6)_______________ (7)_______________ (8)_______________ (9)_______________ (10)_______________.

What do numerous studies show about infants? The human thirst for knowledge is the driving force behind our successful development as a species. But curiosity can also be dangerous, leading to setbacks or even downfalls. Given curiosity’s complexity, scientists have found it hard to define. While pinning down a definition has proven tricky, the general consensus is it’s some means of information gathering. Psychologists also agree curiosity is intrinsically (内在地) motivated. Curiosity covers such a large set of behaviors that there probably isn’t any single “curiosity gene” that makes humans wonder about and explore their environment. That said, curiosity does have a genetic component. Genes and the environment interact in many complex ways to shape individuals and guide their behavior, including their curiosity. Regardless of their genetic makeup, infants have to learn an incredible amount of information in a short time, and curiosity is one of the tools humans have found to accomplish that gigantic task. Hundreds of studies show that infants prefer novelty. It’s what motivates non-human animals, human infants and probably human adults to explore and seek out new things before growing less interested in them after continued exposure. But curiosity often comes with a cost. In some situations, the stakes are low and failure is a healthy part of growth. For instance, many babies are perfectly proficient crawlers, but they decide to try walking because there’s more to see and do when they stand upright. But this milestone comes at a small cost. A study of 12- to 19-month-olds learning how to walk documented that these children fell down a lot. Seventeen times per hour, to be exact. But walking is faster than crawling, so this motivates expert crawlers to transition to walking. Sometimes, however, testing out a new idea can lead to disaster. For instance, the Inuit people of the Arctic regions have created incredible modes to deal with the challenges of living in northern climates, but what we forget about are the tens of thousands of people that tried and failed to make it in those challenging landscapes.A、They are far more curious than adults.B、They prefer to go after all that is novel.C、They have different interests than adults.D、They show non-human animal behaviors.