A new study shows that students learn much better through an active，iterative(迭代的)process that involves working through their misconceptions with fellow students and getting immediate feedback from the instructor.

The research was conducted by a team at the University of British Columbia(UBC)，Vancouver，in Canada，led by physics Nobelist Carl Wieman.In this study，Wieman trained a postdoc，Louis Deslauriers，and a graduate student，Ellen Schelew，in an educational approach，called “deliberate practice，”that asks students to think like scientists and puzzle out problems during class.For 1 week，Deslauriers and Schelew took over one section of an introductory physics course for engineering majors，which met three times for 1 hour.A tenured physics professor continued to teach another large section using the standard lecture format.The results were dramatic: After the intervention，the students in the deliberate practice section did more than twice as well on a 12-question multiple-choice test of the material as those in the control section.They were also more engaged and a post-study survey found that nearly all said they would have liked the entire 15-week course to have been taught in the more interactive manner.

“It’s almost certainly the case that lectures have been ineffective for centuries.But now we’ve figured out a better way to teach”that makes students an active participant in the process，Wieman says.The “deliberate practice”method begins with the instructor giving students a multiple-choice question on a particular concept，which the students discuss in small groups before answering electronically.Their answers reveal their grasp of the topic，which the instructor deals with in a short class discussion before repeating the process with the next concept.

While previous studies have shown that this student-centered method can be more effective than teacher-led instruction，Wieman says tlus study attempted to provide “a particularly clean comparison...to measure exactly what can be learned inside the classroom.”He hopes the study persuades faculty members to stop delivering traditional lectures and “switch over” to a more interactive approach.More than 55 courses at Colorado across several departments now offer that approach，he says，and the same thing is happening gradually at UBC.

How does Wieman look at the traditional lectures according to the third paragraph？

When travelling overseas，do you buy water in plastic bottles or take your chances with tap water?Imagine you are wandering about on a Thai island or __26__ the ruins of Angkor.It's hot so you grab a bottle of water from a local vendor.It's the safe thing to do，right?The bottle is __27__ ，and the label says "pure water".But maybe what's inside is not so __28__ .Would you still be drinking it if you knew that more than 90 percent of all bottled water sold around the world __29__ microplastics?

That's the conclusion of a recently __30__ study，which analysed 259 bottles from 11 brands sold in nine countries，__31__ an average of 325 plastic particles per litre of water.These microplastics included a __32__ commonly known as PET and widely used in the manufacture of clothing and food and __33__ containers.The study was conducted at the State University of New York on behalf of Orb Media，a journalism organisation.About a million bottles are bought every minute，not only by thirsty tourists but also by many of the 2.1 billion worldwide who live with unsafe drinking water.

Confronted with this __34__ ，several bottled-water manufacturers including Nestle and Coca-Cola undertook their own studies using the same methodology.These studies showed that their water did contain microplastics，but far less than the Orb study suggested.Regardless，the World Health Organisation has launched a review into the __35__ health risks of drinking water from plastic bottles.

空白处27.应填

长城
说到中国文化，不能不提到长城。从公元前7世纪到公元16世纪，在大约2 200年的时间里，先后有19个朝代修建过长城，所修的长城长达10万千米以上。主要的长城修建工程是在秦代、汉代和明代完成的。现今存有遗迹的主要是明长城，从东边入海口的山海关(Shanhai Pass)开始，一直到沙漠深处的嘉峪关(Jiayu Pass)，全长约6700千米。长城是世界历史上最伟大的工程之一，其建造时间之长、参与人数之多、工程难度之大，在世界上无出其右。

as conj.（正当）……的时候；如同；由于
　　________至于，关于
　　________好比是，可谓，在某种程度上

Is College a Worthy Investment?

(A）Why are we spending so much money on college? And why are we so unhappy about it? We all seem to agree that a college education is wonderful, and yet strangely we worry when we see families investing so much in this supposedly essential good. Maybe it's time to ask a question that seems almost sacrilegious (大不敬的) : is all this investment in college education really worth it?

(B）The answer, I fear, is no. For an increasing number of lads, the extra time and money spent pursuing a college diploma will leave them worse off than they were before they set foot on campus.

(C）For my entire adult life, a good education has been the most important thing for middle-class households. My parents spent more educating my sister and me than they spent on their house, and they're not the only ones. ..and, of course, for an increasing number of families, most of the cost of their house is actually the cost of living in a good school district. Questioning the value of a college education seems a bit like questioning the value of happiness, or fun.

(D）The average price of all goods and services has risen about 50 percent. But the price of a college education has nearly doubled in that time. Is the education that today's students are getting twice as good? Are new workers twice as smart? Have they become somehow massively more expensive to educate?

(E）Perhaps a bit. Richard Vedder, an Ohio University economics professor, says, "I look at the data, and I see college costs rising faster than inflation up to the nud-1980s by l percent a year. Now I see them rising 3 to 4 percent a year over inflation. What has happened? The federal government has started dropping money out of airplanes. " Aid has increased, subsidized (补贴的) loans have become available, and "the universities have gotten the money. " Economist Bryan Caplan, who is writing a book about education, agrees: "It's a giant waste of resources that will continue as long as the subsidies continue. "

(F）Promotional literature for colleges and student loans often speaks of debt as an "investment in yourself. " But an investment is supposed to generate income to pay off the loans. More than half of all recent graduates are unemployed or in jobs that do not require a degree, and the amount of student-loan debt carried by households has increased more than five times since 1999. These graduates were told that a diploma was all they needed to succeed, but it won't even get them out of the spare bedroom at Mom and Dad's. For many, the most visible result of their four years is the loan payments, which now average hundreds of dollars a month on loan balances in the tens of thousands.

(G）It's true about the money-sort of. College graduates now make 80 percent more than people who have only a high-school diploma, and though there are no precise estimates, the wage premium (高出的部分) for an outstanding school seems to be even higher. But that's not true of every student. It's very easy to spend four years majoring in English literature and come out no more employable than you were before you went in. Conversely, chemical engineers straight out of school can easily make almost four times the wages of an entry-level high-school graduate.

(H）James Heckman, the Nobel Prize-winning economist, has examined how the returns on education break down for individuals with different backgrounds and levels of ability. " Even with these high prices, you're still finding a high return for individuals who are bright and motivated," he says. On the other hand, "if you're not college ready, then the answer is no, it's not worth it. " Experts tend to agree that for the average student, college is still worth it today, but they also agree that the rapid increase in price is eating up more and more of the potential return. For borderline students, tuition (学费) rise can push those returns into negative territory.

(I）Everyone seems to agree that the government, and parents, should be rethinking how we invest in higher education-and that employers need to rethink the increasing use of college degrees as crude screening tools for jobs that don't really require college skills. "Employers seeing a surplus of college graduates and looking to fill jobs are just adding that requirement," says Vedder. "In fact, a college degree becomes a job requirement for becoming a bar-tender. "

(J）We have started to see some change on the finance side. A law passed in 2007 allows many students to cap their loan payment at 10 percent of their income and forgives any balance after 25 years. But of course, that doesn't control the cost of education; it just shifts it to taxpayers. It also encourages graduates to choose lower-paying careers, which reduces the financial return to education still further. "You're subsidizing people to become priests and poets and so forth," says Heckman. "You may think that's a good thing, or you may not. " Either way it will be expensive for the government.

(K）What might be a lot cheaper is putting more kids to work. Caplan notes that work also builds valuable skills-probably more valuable for- kids who don't naturally love sitting in a classroom. Heckman agrees wholeheartedly: " People are different, and those abilities can be shaped. That's what we've learned, and public policy should recognize that. "

(L）Heckman would like to see more apprenticeship-style (学徒式) programs, where kids can learn in the workplace-learn not just specific job skills, but the kind of "soft skills," like getting to work on time and getting along with a team, that are crucial for career success. "It's about having mentors (指导者)and having workplace-based education, "he says." Time and again I've seen examples of this kind of program working.

(M）Ah, but how do we get there from here? With better public policy, hopefully, but also by making better individual decisions. "Historically markets have been able to handle these things," says Vedder," and I think eventually markets will handle this one. If it doesn't improve soon, people are going to wake up and ask, 'Why am I going to college?' "

Over fifty percent of recent college graduates remain unemployed or unable to find a suitable job.