题目

已知两个质数的和是21，其中较小的质数是较大质数的 。 答案：【1】219 在短文的空格内填入适当的词，使其内容通顺，每空格限填一词，首字母已给 Americans think that travel is good for people. Some even think it can help one of the country’s worst problem—crime. (犯罪) Crime worries a lot of people. Every year, the n    1   of crimes goes up and up. They often come from sad homes, with only one parent or no parents at all. There are problems with drugs. (毒品) There are many young criminals (罪犯) in prison. But prison doesn’t change them--60 to 70 percent will go b  2    to crime when they come out of prison. One man, Bob Burton, thought of a new idea. In the old days, young men had to live a hard life on the road. They learned to be strong and brave, and to help their friends in time of danger. This helped them to grow into m   3   . So Bob started “Vision Quest” (幻想探究). He takes young criminals on a long, long j   4     with horses and wagons (马车) 3,000 miles through 7 states. They are on the road for more than one year. The young people on Vision Quest all have bad problems. Most of them have already s  5  time in prison. This is their last chance. It’s hard work on the road. The day starts before the sun comes up. The boys and the girls have to feed the horses. Some of them have never loved anyone before, b   6   they can love their horses. That love can help them to start a new life. Not all young people in Vision Quest will leave crime behind them. 30 or 40 percent will one day be in prison a   7  . But that’s a lot better than 60 or 70 percent. Bob is right. Travel can be good for them.