Last year college students in America spent an estimated $700 on textbooks on average. The National Association of College Stores reported more than five billion dollars in sales of textbooks and course materials. The association spokesman Charles Schmidt says electronic textbooks now just make up 2%~3% of sales. But he says that is expected to reach 10%~15% by 2012. Online versions  are now available for many of the most popular college textbooks. An etextbook can cost half the price of a new print textbook. But students usually lose access to them after the end of the term. And the books cannot be placed on more than one device ,so they are not easy to share. So what do students think of etextbooks?Administrators at Northwest Missouri State University wanted to find it out. Earlier this year they tested them with 500 students in 20 classes. The university is unusual. It provides laptop computers for all 7,000 of its fulltime students. It does not require students to buy their textbooks either. They rent them to save money. The school aims to save even more by moving to etextbooks. The students in the survey reported that downloading the books from the Internet was easy. They liked the idea of carrying lighter backpacks. And 56% said they were better able to find information. But most found that using etextbooks did not change their study habits. And 60% felt they read more when they were reading on paper. In all,almost half the students said they still liked physical textbooks better. But the survey found that cost could be a big influence.55% said they would choose etextbooks if using them meant their textbook rental fee would not increase. Roger Von Holzen heads the Center for Information Technology in Education at Northwest Missouri State University. He tells us that administrators are disappointed with the etextbooks now available because the majority are not interactive . He thinks growth will come when more digital books include video,activities,games and other ways to interact with the information. The technology is improving. But for now,most of the books are just words on a screen. Etextbooks are not better than paper books in that  _  .
they cost more money they're difficult to carry they're not convenient to share they can't be downloaded from the Internet
Question: Last year college students in America spent an estimated $700 on textbooks on average. The National Association of College Stores reported more than five billion dollars in sales of textbooks and course materials. The association spokesman Charles Schmidt says electronic textbooks now just make up 2%~3% of sales. But he says that is expected to reach 10%~15% by 2012. Online versions  are now available for many of the most popular college textbooks. An etextbook can cost half the price of a new print textbook. But students usually lose access to them after the end of the term. And the books cannot be placed on more than one device ,so they are not easy to share. So what do students think of etextbooks?Administrators at Northwest Missouri State University wanted to find it out. Earlier this year they tested them with 500 students in 20 classes. The university is unusual. It provides laptop computers for all 7,000 of its fulltime students. It does not require students to buy their textbooks either. They rent them to save money. The school aims to save even more by moving to etextbooks. The students in the survey reported that downloading the books from the Internet was easy. They liked the idea of carrying lighter backpacks. And 56% said they were better able to find information. But most found that using etextbooks did not change their study habits. And 60% felt they read more when they were reading on paper. In all,almost half the students said they still liked physical textbooks better. But the survey found that cost could be a big influence.55% said they would choose etextbooks if using them meant their textbook rental fee would not increase. Roger Von Holzen heads the Center for Information Technology in Education at Northwest Missouri State University. He tells us that administrators are disappointed with the etextbooks now available because the majority are not interactive . He thinks growth will come when more digital books include video,activities,games and other ways to interact with the information. The technology is improving. But for now,most of the books are just words on a screen. Etextbooks are not better than paper books in that  _  .
A. they cost more money
B. they're difficult to carry
C. they're not convenient to share
D. they can't be downloaded from the Internet
Answer: