题目内容

28、Craig Calfee, was the owner of a bicycle shop, who lived in Santa Cruz, California．On a shining morning one year ago．he was watching his dog, Luna, as it chew （撕咬） a piece of bamboo．But it could not break the bamboo with its powerful jaws （双颚）．In other words, this natural material was strong enough for a good new use．Calfee had an idea．He knew what to do．He set to work making a bicycle out of bamboo．

   Today, he describes his invention as “a little rough”．The bike did work, however．The inventor thought that the bamboo bike might be easy to make and sell in developing countries．He showed his bike on the Internet．Then,  he was contacted by David Ho of the Earth University．The two men travel to Ghana （a country in Africa） to try to produce the bike there．"It's just at the very beginning．We might fail, but it might take （奏效）．" Calfee said．

1．When did Mr. Calfee set to work making a bicycle out of bamboo?

2．Why can bamboo be used to make bicycle?

3．With whom did Mr. Calfee travel to Ghana?

4．Is Ghana a developing country ?