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？

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。

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

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