题目内容
（请给出正确答案）
阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳
Cancer is the second cause of death in the United States, after heart disease. In the __51__, it was often considered a death sentence. But many patients now live longer __52__ of improvements in discovery and treatment.
Researchers say death __53__ in the United States from all cancers combined have fallen for thirty years. Survival rates have increased for most of the top fifteen cancers in both men and women, and for cancers in __54__.
The National Cancer Institute and the Centers for Disease Control and Prevention studied the number of cancer survivors. A cancer survivor is defined __55__ anyone who has been found to have cancer. This would include current patients.
The study covered the period __56__ 1971 to 2001. the researchers found there are three __57__ as many cancer survivors today as there were thirty years ago. In 1971, the United States has about three-million __58__ survivors. Today there are about ten-million.
The study also found that 64% of adults with cancer can expect to still be __59__ in five years. Thirty years ago, the five-year survival rate was 50%. The government wants to __60__ the five-year survival rate to 70% by 2010.
The risk of cancer increases with age. The report says the majority of survivors are 65 years and __61__.
But it says medical improvements have also have also helped children with cancer live __62__ longer. Researchers say 80% of children with cancer will survive at least five years after the discovery. About 75% will survive at __63__ ten years.
In the 1970s, the five-year survival rate for children was about 50%. In the 1960s, most children did not survive cancer. Researchers __64__ they expect more improvements in cancer treatment in the future. In fact, they say traditional cancer-prevention programs are not enough anymore. They say public health programs should also aim to support the __65__ numbers of cancer survivors and their families.
第51题：
A. past B. present C. future D. old
答案
