52. Why does the author say the USDA could have contributed a lot to lowering the climate cost through its dietary guidelines?
- A. It has the capacity and the financial resources to do so.
- B. Its researchers have already submitted relevant proposals.
- C. Its agencies in charge of drafting the guidelines have the expertise.
- D. It can raise students' environmental awareness through its programs.
答案：A
答案句：Not just because of their position of authority: The guidelines drive billions of dollars of food production through federal programs like school lunches and nutrition assistance for the needy.
参考译文：不仅仅是因为它们的权威地位：这些指南通过联邦项目（如学校午餐和对贫困者的营养援助）推动了数十亿美元的食物生产。
定位线索：题干“could have contributed a lot to lowering the climate cost”→答案句“drive billions of dollars of food production”；文中“billions of dollars”对应选项A“financial resources”。
解析：题干问作者为何认为USDA能通过指南降低气候成本，答案句给出两个原因：一是“position of authority”（权威地位），二是“drive billions of dollars of food production”（推动数十亿美元食物生产），即选项A的“capacity and financial resources”。选项B无中生有，原文未提研究者已提交提案；选项C偷换概念，原文未提专业知识；选项D答非所问，原文未提学生环保意识。
54. What may account for the neglect of sustainability in the USDA's Dietary Guidelines according to the author?
- A. Its exclusive concern with Americans' food safety.
- B. Its sole responsibility for providing dietary advice.
- C. Its close ties with the agriculture companies.
- D. Its alleged failure to regulate the industries.
答案：C
答案句：Possibly the agencies in charge of drafting the decisions are too close to the industries they are supposed to regulate. On one hand, the USDA is compiling dietary advice. On the other, their clients are US agriculture companies.
参考译文：可能负责起草决策的机构与它们本应监管的行业关系过于密切。一方面，美国农业部正在编制饮食建议。另一方面，它们的客户是美国农业公司。
定位线索：题干“what may account for the neglect”→答案句“too close to the industries”；文中“clients are US agriculture companies”对应选项C“close ties with the agriculture companies”。
解析：题干问忽视可持续性的原因，答案句指出机构“too close to the industries”，且“clients are US agriculture companies”，即选项C“close ties with the agriculture companies”。选项A偷换概念，原文未提食品安全；选项B以偏概全，提供饮食建议只是部分原因；选项D偷换概念，原文未说监管失败。