What is the first paragraph mainly about? 
What is the first paragraph mainly about?A、Common causes of cancers.
B、Treatments for different cancers.
C、Traditional bliefs on cancer.
D、People’s attitudes to cancer patients.
【正确答案】：A
【题目解析】：判断推理题。第一段主要描述了引起癌症常见的原因，其中代表性的短语有attribute……to……，be caused by……，所以答案A正确；第一段中没有涉及到其他选项的内容。