46.What can we learn about marriage vows from the passage?
答案：A they may not guarantee a lasting marriage
解析：通过 marriage vows 可定位到文章第一段，But a new study finds that the risk of divorce among older married couples rises when the wife—but not the husband—becomes seriously ill.说明vows并不能保证长久的婚姻关系。而且结合下文可以看出在疾病面前，尤其是当妻子生病后，婚姻关系更容易破裂。其他选项都与这个主题不符合。所以不选。
47.What did Karraker and co-author Kenzie Latham find about elderly husbands?
答案：47B They can become increasingly vulnerable to serious illnesses.
解析：通过 题干可定位至原文第四段：The incidence of new chronic illness onset increased over time as well, with more husbands than wives developing serious health problems.根据句意随着时间的增长，新的慢性病的发病率也随之增高，在患病的夫妻当中，丈夫的数量超过妻子。同时第五段中也有相关的句子。“We found that women are doubly vulnerable to marital dissolution in the face of illness,” Karraker said. “They are more likely to be widowed, and if they are the ones who become ill, they are more likely to get divorced.”
四个选项中，B比较符合原文，contract serious illnesses than their wives与 more husbands than wives developing serious health problems.
48.What does Karraker say about women who fall ill?
答案：48B they are more likely to get divorced
解析：由题目顺序和题干定位到第五段 “They are more likely to be widowed, and if they are the ones who become ill, they are more likely to get divorced.”大意为，如果丈夫得重病，妻子更容易成为寡妇，而如果她们得病，则可能以离婚结束。A选项和原文相反，C与D选项原文没有明确的信息。
49.Why is it more difficult for men to take care of their sick spouses according to Karraker?
答案：49A they are more accustomed to receiving care
解析：通过题干定位到第六段“Gender norms and social expectations about care-giving may make it more difficult for men to provide care to ill spouses,” 词句大意是性别的常态（在照顾人方面）以及社会的看法导致男性很难做到照顾生病的配偶。其他选项都不符合原文的意思。
50.What does Karraker think is also important?
答案：50C providing extra care for divorced women
解析：由题干定位到最后一段，“Offering support services to spousal caregivers may reduce marital strain and prevent divorce at older ages,” she said. “But it’s also important to recognize that the impetus for divorce may be health-related and that sick ex-wives may need additional care and services to prevent worsening health and increased health expenditures.” 可以看出，本段有两层观点，题目问题对应第二层观点，即由于疾病导致守寡的女性需要社会额外地照顾，防止女性健康恶化，增加医疗方面的开支。由此答案选择C.