题目

如果a、b都是有理数，且a﹣b一定是正数，那么（） A . a、b一定都是正数 B . a的绝对值大于b的绝对值 C . b的绝对值小，且b是负数 D . a一定比b大 答案：D 阅读理解 　　School districts are turning to high-tech solutions-from fingerprint scans to electronic cards－to track kids on school buses and keep them from getting off at the wrong stops．A fingerprint scanning system, approved this month for testing at the Desert Sands district, northeast of San Diego．Students will be scanned as they get on and off the bus． 　　"Kids get lost．It happens in every school district, every year," says John DeVries, president of Global Biometrics Security, which developed the Biometric Observation Security System(BOSS)that's being tested．It happened Oct．13 when a Prince George's County(Md．)school employee took a 5-year-old student to the wrong bus and the student got off several blocks from home． 　　With BOSS, students' fingerprints are scanned and sent to a database．When they get off, they provide a "check out" print．An alarm sounds if the child tries to get off at the wrong place．The fingerprints are not stored, DeVries says．They are converted into a series of numbers that cannot be used to re-create the print, he says． 　　Margaret Gomez of Palm Springs, Calif．, whose daughter, then 6, was let off a bus about a mile from her home three years ago, supports the idea．"Anything is better than what they have in place now．" 　　Other tracking systems include the ZPass from Seattle-based Zonar Systems, which uses a programmed card carried by students or tied to a backpack．It is in about 30 districts, including North Kansas City Schools and Illinois School District 128 in Palos Heights, company executive Chris Oliver says． 　　Paul Stephens, of the Privacy Rights Clearinghouse in San Diego, says tracking students is reasonable, but the data could fall into unauthorized hands．"What if a child predator was able to get access to this?" he says． (1) What is the purpose of schools turning to high-tech solutions? [　　] A． To make school buses safer for kids． B． To prevent kids from getting lost． C． To help parents locate their missing kids． D． To save some time for school children． (2) What can we learn from the third paragraph? [　　] A． Students will have to carry a database with them． B． An alarm will go off every time kids get off C． The fingerprints will be stored in the database． D． Students' information can't be used for other purposes． (3) What is Margaret Gomez's attitude toward the new solution? [　　] A． Supportive． B． Pessimistic． C． Doubtful． D． Worried． (4) What is Paul Stephens mainly concerned about? [　　] A． Whether this new solution is reasonable． B． How this tracking can be accepted by parents． C． The safety of children's personal information． D． Who should be authorized access to such information．