阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

          The adobe dwellings (土坯房)    （build）by the Pueblo Indians of the AmericanSouthwest are admired by even  most modern of architects and engineers. In addition to their simple beauty, what makes the adobe dwellings admirable is their  (able) to “air condition” a house without ( use) electric equipment. Walls made of adobe take in the heat from the sun on hot days and give out that heat  ( slow) during cool nights, thus warming the house. When a new day breaks, the walls have given up their heat and are now cold enough (cool) the house during the hot day; the same time, they warm up again for the night. This cycle       (go) day after day: The walls warm up during the day and cool off during the night and are thus always a timely offset(抵消) for the outside temperatures. As   (nature) architects, the Pueblo Indians figured out exactly   thick the adobe walls needed to be to make the cycle work on most days.