单选题 Pathways to Research: Problem-solving 　　1. Pittsburgh's many hills aren't kind to bikers. Anyone hoping to pedal to work there has to contend with steep streets like Canton Avenue, which famously climbs at a nearly 40-degree angle. As a result, some residents avoid biking altogether. 　　2. But University of Pittsburgh graduate Micah Toll, 23, and a few friends recently launched an invention that they hope will increase the city's pedal power. An electric bike called to Pulse PEVO. A super-strong battery powers the bicycle. Able to hit nearly 20 miles per hours without pedaling, it zips battery powers the bicycle. Able to hit nearly 20 miles per hour without pedaling , it zips up the city's most daunting(令人却步的)hills.Toll hopes it will persuade people in Pittsburgh and elsewhere to get out of their cars and onto bikes. 　　3. If it sounds like Toll has a knack(窍门) for fixing problems, that's because he does. In high school, he designed a new type of construction beam. It weights no more than a feather pillow but can be used to build sturdy(坚固的)homes for refugees fleeing war or natural disaster.For his work, Toll was invited to attend the Inter International Science and Engineering Fair(ISEF)—twice, in 2006 and 2007. The annual competition for young researchers is program of Society for Science&the Public(that's the parent organization of Science News for Kids).Toll says that when it comes to science, he keeps it simple："You see a problem and say, "How could I solve that?" 　　4. He's not the only to take that approach. Many young researchers get their start by trying to solve a problem or fulfill a need in their own communities.When students dedicate themselves to finding a solution that many benefit their community, "a passion is ignited(点燃), "says Wendy Hawkins, executive director of the Inter Foundation, which sponsors Intel ISEF."Finding that passion and fostering it can be the key to many students future success."she says.