A window is more than just an opening that you can see through. It can affect the way a building looks,how much energy a building USES and even how you feel.     Scientists are now working on ncw technologies to create"smart windows". Unlike normal windows,high-tech smart windows can change from clear to dark and back again with the touch of a button --or even automatically as the outside light  changes. Smart windows have the power to make the world a cleaner and more comfortable place. Instead of turning on air conditioners ,people could simply  _ the windows in a building's empty rooms. With the rooms less bright,they would stay cool,and people would save energy and money at the same time.     That's why smart windows are so exciting. Says Claes Granqvist. He's a professor of physics at Uppsala University in Sweden. If you think that you don't care much about windows,you should think again,Granqvist says. Most people who live in developed countries spend about 90% of their time inside buildings and cars. You might spend even more time than that indoors during the winter if you live in a cold climate.     Imagine then what it would be like if there were no windows. You'd have no idea what's going on outside. So,the light of the nature is important for improving the way people feel when they stay indoors. The development of smart windows could mean that a lot of air-conditioning systems may no longer be needed. "In the future," Granqvist says "our buildings may look different." The author would probably disagree with that  _  .
smart windows are not as good as air conditioners for conditioning air windows are not only openings that you can see through the character of a building is connected to its windows natural light:makes people feel better when they stay indoors.
Question: A window is more than just an opening that you can see through. It can affect the way a building looks,how much energy a building USES and even how you feel.     Scientists are now working on ncw technologies to create"smart windows". Unlike normal windows,high-tech smart windows can change from clear to dark and back again with the touch of a button --or even automatically as the outside light  changes. Smart windows have the power to make the world a cleaner and more comfortable place. Instead of turning on air conditioners ,people could simply  _ the windows in a building's empty rooms. With the rooms less bright,they would stay cool,and people would save energy and money at the same time.     That's why smart windows are so exciting. Says Claes Granqvist. He's a professor of physics at Uppsala University in Sweden. If you think that you don't care much about windows,you should think again,Granqvist says. Most people who live in developed countries spend about 90% of their time inside buildings and cars. You might spend even more time than that indoors during the winter if you live in a cold climate.     Imagine then what it would be like if there were no windows. You'd have no idea what's going on outside. So,the light of the nature is important for improving the way people feel when they stay indoors. The development of smart windows could mean that a lot of air-conditioning systems may no longer be needed. "In the future," Granqvist says "our buildings may look different." The author would probably disagree with that  _  .
A. smart windows are not as good as air conditioners for conditioning air
B. windows are not only openings that you can see through
C. the character of a building is connected to its windows
D. natural light:makes people feel better when they stay indoors.
Answer: