根据下列文章,请回答 31～35 题。 Global Cancer Rates to Rise by 50%by 2020 The number of newcancer cases worldwide is expected to；increase by 50%by the year 2020．But a new report suggests that asmany as a third of new cancers could be avoided by adopting healthier lifestyles and through public healthaction． The World CancerReport，released by the International Agency for Research on Cancer, shows that cancer has now emerged asa major public health threat in；developing countries as well as rich ones．Overall．cancerwas responsible for 12%Of all deaths il3 2000．But in many countries more than aquarter of all deaths are caused by cancer． The reportshows that l o million new cancers were diagnosed globally in 2000，and that numberis expected to rise t0 1 5 million by 2020．Researchers say most of thatincrease will mainly be due to steadily aging populations in both developed and,developing countries and current trends in smoking and other unhealthy habits． ”Cancer has emerged as a major public healthproblem in developing countries for the first time，matching its effect inindustrialized(工业化的)countries，”said researcher Paul Kleihues，MD．director of IARC，ina news release．”once considered a ”western, disease，the Report highlights thatmore than 50 percent of the world’s cancer burden．in” terms of both numbers ofcases and deaths．already Occurs in developing countries．” The risk of beingdiagnosed with cancer in developed countries is double that in less-developedones．However, the risk of dying from cancer is much bigger in developed countries，where80%of cancer patients already have late—stage incurable tumors(肿瘤)at the timeof diagnosis． Researchers say Cancer rates have traditionallybeen higher in developed countries due to greater exposure to tobacc0，occupationalcarcinogens(致癌物)，and an unhealthy Western diet and lifestyle．As less—developedcountries become industrialized and more prosperous。they tend to adopt thehigh—fat diet and low physical activity levels typically seen In the West，whichincrease cancer rates． 第 31 题 The report says that steps could be taken toreduce about