C

　　MOOC, a massive(大规模的) open online course, aims at providing interactive discussion and open access via the web. In addition to traditional course materials such as videos, readings, and problem sets, MOOCs provide interactive user forums (论坛) that help build a community for the students, professors, and teaching assistants.

　　MOOCs first made waves in the fall of 2011, when Professor Sebastian Thrun from Stanford University opened his graduate-level artificial intelligence course up to any student anywhere, and 160,000 students in more than 190 countries signed up. This new kind of online classes is shaking up the higher education world in many ways. Since the courses can be taken by hundreds of thousands of students at the same time, the number of universities might decrease greatly. Professor Thrun has even imagined a future in which there will only need to be 10 universities in the world. Perhaps the most impressive thing about MOOCs, many of which are being taught by professors at prestigious (声誉高的) universities, is that they're free. This is certainly good news for cash-strapped students.

　　There is a lot of excitement and fear about MOOCs. While some say free online courses are a great way to increase the enrollment (注册) of students who are lack of resources, some critics (批评者) have said that MOOCs encourage an unrealistic one-size-fits-all model of higher education and that there is no replacement for true dialogues between professors and their students. After all, a brain is not a computer. We are not blank hard drives waiting to be filled with data. People learn from people they love and remember the things that arouse emotion. Some critics worry that online students will miss out on the social aspects of college.

28. What can we learn about MOOCs?

A. It is cheap to take the courses.

B. Most courses are about artificial intelligence.

C. They have decreased the number of universities.

D. Many courses are offered by professors from famous universities.

29. The"cash-strapped students"in the second paragraph refers to students who are_________.

A. fond of money B. short of money C. careful with money D. familiar with money

30. What might be one of the disadvantages of MOOCs?

A. The limited courses offered around the world.

B. The disappearance of traditional course materials.

C. The overreliance on professors from good universities.

D.The lack of social interaction among students and professors.

31. What is the purpose of the text?

A. To give an introduction of MOOCs.

B. To put an advertisement for MOOCs.

C. To describe the influence of artificial intelligence.

D. To express a critical attitude towards artificial intelligence.

　　Jim Denevan is an amazing artist whose work is admired by all, but owned by none一that's because all of Jim's art is created on an unusual canvas (画布)一the soft sand. He sometimes spends days working on a piece, only to see it washed away by the sea or a storm and that is just the way he likes it.

Denevan discovered his artistic talents about ten years ago, when he was wandering aimlessly on the beach with a stick. He ended up drawing a 12-foot-long fish. Since then, Jim has traveled over 1,800 miles while creating over 600 pieces of sand art.