46. What do we learn from the passage about reverse graffiti?
- A. It uses paint to create anti-pollution images.
- B. It creates a lot of trouble for local residents.
- C. It causes lots of distraction to drivers.
- D. It turns dirty walls into artistic works.
答案：D
答案句：They find dirty surfaces and paint them with images or messages using cleaning brushes or pressure hoses (高压水管) . Either way, it's the same principle: the image is made by cleaning away the dirt.
参考译文：他们找到脏污的表面，用清洁刷或高压水管在上面绘制图像或信息。无论哪种方式，原理都是一样的：图像是通过清除污垢而制成的。
定位线索：题干“What do we learn from the passage about reverse graffiti”→答案句取自第1段“They find dirty surfaces and paint them with images or messages using cleaning brushes or pressure hoses”；文中“paint them with images”对应选项D“turns dirty walls into artistic works”。
解析：题干问关于reverse graffiti我们能了解到什么。答案句明确指出艺术家用清洁工具在脏表面上创作图像，即把脏墙变成艺术作品，对应D项。A项说用油漆，文中是清洁工具，偷换概念；B项说给居民带来麻烦，文中未提；C项说分散司机注意力，文中未提。
50. How did Sao Paulo city officials handle Alexandre Orion's reverse graffiti?
- A. They made him clean all the tunnels in Sao Paulo.
- B. They took drastic action to ban all reverse graffiti.
- C. They charged him with polluting tunnels in the city.
- D. They made it impossible for him to practice his art.
答案：D
答案句：The city officials then decided to take drastic action. They not only cleaned the whole tunnel but every tunnel in Sao Paulo.
参考译文：市政官员随后决定采取严厉措施。他们不仅清理了整条隧道，还清理了圣保罗的每条隧道。
定位线索：题干“How did Sao Paulo city officials handle Alexandre Orion's reverse graffiti”→答案句取自第4段“They not only cleaned the whole tunnel but every tunnel in Sao Paulo”；文中“cleaned the whole tunnel but every tunnel”对应选项D“They made it impossible for him to practice his art”。
解析：题干问圣保罗官员如何处理Orion的涂鸦。答案句说明他们清理了所有隧道，使Orion找不到脏表面继续创作，从而无法实践他的艺术，对应D项。A项说让Orion清理隧道，文中是官员自己清理；B项说禁止所有涂鸦，文中未提；C项说指控他污染隧道，文中说“找不到什么可指控的”。