047.
Nowadays in the United States, more and more people are beginning to build underground houses which save open land. When houses are underground, there is more land for parks, playgrounds and gardens. Underground houses also save energy. They use only a little energy to stay warm or cool.
As we know, the idea of underground houses is very old. People in the past lived in underground hosues and underground cities in China. And today you can find large underground shopping centers in China, Japan, South Korea and Canada as well. Some countries also build underground factories and shop-houses to hold things.
Joyce Rinker has an underground house in Michigan. One day in February, the outside temperature was a cold -22℃, but the temperature inside his house was a warm 16℃. The next year, in July, the outside temperature was a hot 42℃, but the temperature inside was a comfortable 22℃.

答案解析：
(1) 正確答案為C。根據build underground houses which save open land建造地下房屋可以節省空地，以及Underground houses also save energy.地下房屋也節省能源?？芍藗兘ㄔ斓叵路课莸脑蚴枪澥⊥恋睾湍茉?，因此C項正確。
(2) 正確答案為C。根據People in the past lived in underground hosues and underground cities in China.過去，中國民眾生活在地下房屋和地下城市中?？芍?，使用了很長時間地下房屋的是中國，因此C項正確。
(3) 正確答案為B。根據the outside temperature was a cold -22℃, but the temperature inside his house was a warm 16℃. 外面的溫度已經是零下22度了，而他屋里的溫度是溫暖的16度。因此可知外面零下22度時，他屋里是16度，因此B項正確。