Unit 24 课时跟踪练(一) Warmup & Lesson 1 - Prereading

　　Ⅰ.阅读理解

　　A

　　There was a time when a trip to the supermarket in the United States often ended with a seemingly simple question from the cashier (收银员): "Paper or plastic？" Well, which type of bag would you choose?

　　While all types of bags have some influence on the environment, it has long been supposed that paper bags are kinder. They are made from a renewable source, break down easily, burn without giving off thick smoke and can be recycled (回收利用). However, the producing process behind paper bags uses more energy than that of plastic ones. How can this be true?

　　Studies show that paper bag production requires four times as much energy as plastic bag production. And the amount (量) of water used to make them is twenty times higher. Besides, the influence on forests is very serious. It takes about fourteen million trees to produce ten billion paper bags, which happens to be the number of bags used in the United States yearly. In terms of recycling, the idea that paper bags are more environment­friendly than plastic ones can be quickly discarded. Research shows it requires about 98% less energy to recycle plastic than it does paper.

　　Even though paper bags might be more harmful than plastic ones, plastic still seems to be considered by governments as the more harmful of the two. In Ireland, for example, a tax (税) has been introduced to discourage the use of plastic bags. People have to pay 22 cents for every plastic bag, and as a result, their use has dropped quickly.

　　There's no doubt it makes more sense to reuse these bags. However, we don't seem to be doing that at present. That may be because they fall apart quickly. If so, cloth bags are a better choice, but still, their production also has a bad influence on the environment. So what to do? How should we answer the question of "Paper or plastic？" It seems that we first need to ask ourselves one more general question: "What can I do to help the environment？"

　　语篇解读：本文是议论文。购物时，应该选用纸袋还是塑料袋，抑或是其他更加环保的方式？作者主要就此进行了探讨。

　　1．The questions in Paragraph 1 are used to ________.

　　A．express the author's doubts

　　B．tell readers how to save money

　　C．introduce points for discussion

　　D．show the kindness of the cashier

　　解析：选C　写作手法题。作者在首段中通过两个问题，引出了下文要探讨的话题：购物时，应该选纸袋还是塑料袋，到底哪种更环保呢？

　　2．Compared with plastic bags, paper bags ________.

A．need more water to produce