1 . Suppose you find a bright yellow bike on a street corner in the city. You hop on (跨上) it and _______. But wait — isn’t this stealing? No, it isn’t._______ shouts, “Stop! Thief!” That is _______ this free ride is just fine with the city.

You _______ find hundreds of free yellow bikes in some US cities. The idea began in Portland, Oregon, in 1994. People saw a need for _______ transportation, and they wanted to help _______ pollution. So, to get citizens (市民)_______ their cars and onto pollution-free bikes, they _______ the Yellow Bike Project.

The _______ bikes are painted bright yellow and placed throughout the city. People can hop on the yellow bike and ride to run errands (短程差事), to work ________ to school. Then, they leave the bike for the ________ rider. There have been times when bikes have been stolen, but most people ________ the rules, because they think it is not wise to ________ the bike that’s already free.

Portland’s ________ was quickly loved by a lot of people. Within two years of its starts, similar programs were ________ in cities in six other states.