When Melissa Mahan and her husband visited the Netherlands, they felt imprisoned by their tour bus. It forced them to see the city according to a particular route and specific schedule--but going off on their own meant missing out on the information provided by the guide. On their return home to San Diego, California, they started a new company called Tour Coupes. Now, when tourists in San Diego rent one of their small, brightly coloured three-wheeled vehicles, they are treated to a narration over the stereo system about the places they pass, triggered by Global Positioning System (GPS) satellite technology.
This is just one example of how GPS is being used to provide new services to tourists. "What we really have here is a technology that allows people to forget about the technology," says Jim Carrier of IntelliTours, a GPS tourism firm which began offering a similar service over a year ago in Montgomery, Alabama. The city is packed with sites associated with t
A. event
B. a local branch of an organization
C. division of a book
D. period of time
Scientists who believe cell phones are dangerous have been throwing out hypotheses to explain away the negative results. Maybe something about the (34) animals raised their rates of cancer or sperm problems, so (35) the exposed animals didn’t seem to be harmed. Maybe the studies should have used pulsed, (36) radiation rather than a continuous beam, the better to (37) the way we actually use mobile phones. Maybe it matters (38) the lab animals are zapped (39) in a device like a Ferris wheel or while (40) around in cages. On the other hand, if these details do (41) , maybe that in itself is significant.
Scientists who (42) claims that cell-phone radiation is causing an epidemic of brain cancer (43) that there isn’t any mechanism. (44) textbook biophysics, only radiation that has enough energy to ionize molecules—that is, knock off electrons—can (45)
A. when
B. which
C. where
D. whether
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