题目

下列是对20世纪五十年代新中国经济成分变化情况的分析，不正确的是 年份/比重国营经济合作社经济公私合营经济资本主义经济个体经济 1952年19.1％1.5％0.7％6.9％71.8％ 1956年32.2％53.49％7.3％07.1％ A.1952年分散的私有制经济占据主体地位       B.合作社经济不是公有制的经济 C.到1956年，建立了社会主义的经济基础      D.对资本主义经济进行彻底改造   If you thought taking vitamins would reduce the risk of lung cancer, think again．   Researchers who studied 77，721 people said on Friday that people who took too much vitamin E，especially smokers，had a small but higher risk(风险) of developing lung cancer．    They tracked the subjects’use of multi-vitamins，vitamin C and vitamin E to see if it offered protection from lung cancer．But they found that none of the vitamins was tied to a reduced risk．  “If you could find some sort of magic pill―a pill you could take once a day to decrease your risk―that would be wonderful．But unfortunately．we didn’t find that in our study,”lead researcher Christopher Slatore，of the University of Washington Seattle，said．    The subjects of the study were followed for four years，and 521 developed lung cancer，the majority of them smokers or former smokers，Slatore’s team reported in the American Journal of Respiratory and Critical Care Medicine．        Among those in the study who developed lung cancer, the researchers saw a small increased risk related with vitamin E supplements(补充剂)in addition to the expected connections to smoking，family history and age．    This added up to a 28 percent increased risk of developing lung cancer for those taking 400 mg of vitamin E supplements daily for 10 years，the researchers said．    “For people―especially smokers―I suggest that they not take vitamin E(as a supplement) unless they have a very strong reason to take it．” Slatore said．    The idea that vitamin supplements are healthful，or at least not harmful．comes from the desire of many people to match the benefits of a healthful diet with a convenient pill，Tim Byers of the University of Colorado School of Medicine．wrote in an essay．53．The writer thinks the statement“taking vitamins would reduce the risk of lung cancer，is         .  A．wrong    B．right    C．doubtful  D．possible54．According to the study of researchers，         may increase the risk of lung cancer.  A．the heavy smokers’sudden stop of smoking  B．use of multi-vitamins instead of a healthy diet  C．taking 400 mg of vitamin C supplements daily for a year  D．vitamin E supplements，smoking，family history and age55．According to the passage，many people take vitamin supplements to          A．cure lung cancer caused by family history  B．prevent diseases like cancer and heart attack  C．save the trouble of making a healthful diet  D．reduce the pain caused by lung cancer56．What is the main idea of the passage?  A．Taking vitamins would reduce the risk of lung cancer．  B．Vitamins are no guard against lung cancer．  C．Vitamin supplements are convenient and magic．  D．Vitamins ale harmful，or at least not healthful．