第9题: [单项选择]Exposure to asbestos fibers can cause cancer_____ A. only when asbestos is used in building industry B. only when it is used in large quantities C. even if it is used in small quantities D. if they are used when wet rather than dry 参考答案:C 答案解析:第二段第三句指出,研究表明,接触少量的石棉纤维就可以直接造成癌症、石棉沉滞症和其他疾病的发生。