[解析]
(1)B.推理判断题.根据第一段第二句 In a recent letter,the American Medical Association (AMA) urged big social media including Amazon,Facebook and Google to take action to defend medical science on their platforms(在最近的一封信中,美国医学协会(AMA)敦促包括亚马逊、Facebook和谷歌在内的大型社交媒体采取行动,在它们的平台上捍卫医学科学.)可知,美国医学会要求社交媒体在其平台上阻止发布疫苗的错误信息.故选B.
(2)C.推理判断题.根据第二段It said that vaccine﹣preventable diseases that do harm to the public health like measles (麻疹)are on the rise.Measles cases worldwide jumped more than 30% in 2017 compared to 2016,with the largest increases seen among nations in the Americas,Europe and the Eastern Mediterranean.Vaccine﹣ preventable diseases are increasing largely because many people are unwilling to get vaccinated.And some of these people even encourage others to refuse vaccination.So this year,the World Health Organization (WHO) declared the anti﹣vaccination movement a top 10﹣health threat(它说,危害公共卫生的疾病比如麻疹这样的疫苗可预防的疾病正在越来越多.与2016年相比,2017年全球麻疹病例增加了30%以上,其中美洲、欧洲和东地中海国家增幅最大.疫苗可预防的疾病正在大量增加,因为许多人不愿意接种疫苗.有些人甚至鼓励其他人拒绝接种疫苗.因此,今年世界卫生组织(WHO)宣布反疫苗运动是十大健康威胁之一.)可知.作者提到麻疹病例是为了说明不接种疫苗的后果.故选C.
(3)A.推理判断题.根据第四段A research article published in 1998 in a medical journal suggested a link between a vaccine and the development of autism(自闭症) in young children.1998年发表在医学杂志上的一篇研究文章指出,疫苗与儿童自闭症(孤独症)的发展之间存在联系.Another reason for the growth in the anti﹣vaccination movement is widespread misinformation on social media,which can turn people against vaccination.另一个原因是在社会媒体上,反疫苗运动的发展是广泛的错误信息,这会使人们反对疫苗接种.和If a concerned parent consistently sees information in their News feed that casts doubt on the safety of vaccines,it could cause them to disregard the advice of their children's physicians and public health experts and refuse to follow the recommended vaccination schedule.如果一个关心的家长在他们的新闻中持续看到对疫苗安全性产生怀疑的信息,这可能会使他们忽视他们孩子的医生和公共卫生部门的建议专家和拒绝遵循推荐的疫苗接种计划,可知人们对疫苗安全性的担忧,与孤独症有关的疫苗接种研究和 错误信息在社交媒体平台上传播会对反接种运动起作用,没有提到费用.故选A.
(4)C.作者态度题.根据最后一段Another reason for the growth in the anti﹣vaccination movement is widespread misinformation on social media,which can turn people against vaccination.另一个原因是在社会媒体上,反疫苗运动的发展是广泛的错误信息,这会使人们反对疫苗接种.可知作者对疫苗接种的态度是积极的.A.Doubtful怀疑的;B.Ambiguous 模棱两可的;C.Positive积极的;D.Negative消极的.故选C.