阅读理解。 PDAs are very useful. They are like small computers. You can put a lot of information into them. For example, you can put in the telephone and e-mail addresses. Many people use PDAs to remember important dates. Some of these super machines can even send and receive e-mails. PDAs are small and convenient. A few years ago, they were expensive. Now, they are cheap. Many people use them at work and at school. People can carry PDAs in their pockets. But, it's important to be careful. These little machines are easy to lose (丢失). People put such important information into their PDAs. It's really terrible to lose them. 1. What's the main idea of the passage? [     ] A. PDAs are like small computers. B. You can do many things with a PDA. C. PDAs are cheap. D. Too many people use PDAs. 2. The passage does not say a PDA can ______. [     ] A. send e-mails B. remember information C. talk to you D. do some things like a computer 3. What do we learn about PDAs? [     ] A. Students don't like to use them. B. All of them can send and receive e-mails. C. They are very large. D. They aren't very expensive. 4. Losing a PDA is a ______ experience (经历). [     ] A. great B. fine C. strange D. bad 5. What kind of person would not use a PDA? [     ] A. Someone who hates computers. B. A student. C. A person with a busy time table. D. A business (商) person.