46.What can we learn about marriage vows from the passage?
答案：A they may not guarantee a lasting marriage
解析：通過 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.說明vows并不能保證長久的婚姻關系。而且結合下文可以看出在疾病面前，尤其是當妻子生病后，婚姻關系更容易破裂。其他選項都與這個主題不符合。所以不選。
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：通過 題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.根據句意隨著時間的增長，新的慢性病的發病率也隨之增高，在患病的夫妻當中，丈夫的數量超過妻子。同時第五段中也有相關的句子。“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.”
四個選項中，B比較符合原文，contract serious illnesses than their wives與 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：由題目順序和題干定位到第五段?“They are more likely to be widowed, and if they are the ones who become ill, they are more likely to get divorced.”大意為，如果丈夫得重病，妻子更容易成為寡婦，而如果她們得病，則可能以離婚結束。A選項和原文相反，C與D選項原文沒有明確的信息。
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：通過題干定位到第六段“Gender norms and social expectations about care-giving may make it more difficult for men to provide care to ill spouses,”?詞句大意是性別的常態（在照顧人方面）以及社會的看法導致男性很難做到照顧生病的配偶。其他選項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：由題干定位到最后一段，“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，本段有兩層觀點，題目問題對應第二層觀點，即由于疾病導致守寡的女性需要社會額外地照顧，防止女性健康惡化，增加醫療方面的開支。由此答案選擇C.