2． When are windows the weak link in a building?
A In the cold winter．
B In the hot summer．
C When air conditioners are turned on．
D Both A and B．
3． What are smart windows，according to Paragraph 4?
A Windows that are coated．
B Windows that are glazed．
C Windows the color of which can be changed．
D Windows that have many layers．
4．To make electrochromic windows change color，what is applied to the window glass?
A Electricity．
B Tungsten oxide．
C A battery．
D A voltage．
5． What will he the benefit if the research on smart windows turns out to be
successful，according to the last paragraph?
A The buildings will look different．
B Windows can be as large as you want．
C We may not need air conditioners any more．
D They are less expensive than traditional windows．
答案与题解：
1． A 第一段告诉我们窗户因为让阳光进入房间，并且为房间提供热源，所以节约了能源。第二段说，窗户使人们能接触外部世界。所以B、C和D都说明了窗户的重要性。第一段最后一句说，研究者正在实验能让窗户变换亮度，但并没有说已经实验成功，所以A是错误的说法，是正确选择。
2． D 短文第三段的第一句说：windows are the weak link in a building，接下来是对这句话分寒冬和炎夏做了说明。所以D是正确选择。
3． C 第四段告诉我们，多年来，科学家已研究出多种通过窗户节能的办法，而smart windows 使用的技术使窗户能变换颜色。所以C是正确选择。
4． B 第五段第二句提供了答案。a sheet of glass coated with thin layers of chemical compound such as tungsten oxide中的coated是“涂上一层薄薄的……”的意思。
5． C 短文最后一段的第五句提供了答案。