Nowadays in the United States, more and more people are76.__对_________
beginning to build underground houses where save open land. 77.___that/which___
When houses are underground, there are more land for parks,78. _____is____
playgrounds and gardens. Underground house also save energy. 79. _houses_____
They use only a few energy to stay warm or cool. As we know, 80. _little________
the idea underground houses is very old. People in the past81. _后加_of________
live in underground houses and underground cities in China. And 82. _____lived_____
today you can’t find large underground shopping centers in China, 83.____can____
Japan, South Korea and Canada as well as . Some countries also 84.去掉as______
build underground factories and shop-houses to held things.85. ____hold______
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