Question 18 is based on the recording you have just heard.

Recording One

听力原文

        While it has long been a practice in Asian countries, many people in Western countries have yet to embrace the “No Shoes in the House” rule. For many in those countries, wiping their shoes before going inside is regarded as sufficient. (16) [After all, they may think a little dirt doesn’t hurt anyone.] But I can give you several good reasons why people should remove their shoes before going inside their homes.

         Bacteria are everywhere, they collect on your shoes when you walk along sidewalks, public-toilet floors and even office carpets. In one study conducted at an American university, researchers collected microscopic germs from footwear. (17) [They found that up to 421,000 units of bacteria can collect on the outside of a single shoe.] And it only takes a little bit of dirt to damage your timber floors. The more dirt you track in, the more it scratches, and the more often you have to clean, the extra scrubbing will harm your floors over time. Shoes can also leave marks and scratches on floors, especially high heels or shoes with pointy or hard parts. These can dent and scratch your floor. And if you live in an apartment building, removing your noisy shoes is the polite thing to do out of consideration for your downstairs neighbors. Walking around with bare feet is actually better for your feet. It strengthens the muscles in your feet. Though many people are accustomed to wearing shoes during all their waking hours. The more time you spend wearing shoes, the more likely you are to incur foot injuries as a result.

        And if people aren’t yet convinced by my arguments, I can give one final reason. (18) [The dust and toxic chemicals you bring into your house via your shoes can deteriorate the air quality in your home.] Toxic chemicals are everywhere in our lives: insect killing chemicals used on public grass areas; cleaning chemicals on the floors of public areas. By kicking off your shoes before you enter the home, you are denying entry to these harmful chemicals. Given the amount of time we spend in classrooms and the number of shoes that passed through them every day, you may well understand me if I were to propose a “No Shoes in the Classroom” rule.

18. What is the final reason the speaker gives for removing shoes before entering a house?（讲话者给出的进屋前脱鞋的最后一个理由是什么？）

解析：A。录音中讲话人提到，可以给出最后一个理由（one final reason）：通过鞋子带入家中的灰尘和有毒化学品会恶化家中的空气质量。A项中的chemicals和deteriorate air quality原词复现，故为正确答案。

错项排除：录音中提到，如果住在公寓楼里，出于对楼下邻居的考虑，脱下有噪音的鞋子（noisy shoes）是礼貌之举，并不是说鞋子的噪音会使家人心烦意乱，故B项排除。C项利用录音中的marks进行干扰，但hard to erase在录音中无依据，故排除。录音中间部分提到，鞋子也会在地板上留下痕迹和刮痕，但这不是讲话者给出的最后理由，故D项排除。