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) 1 (build) by the Pueblo Indians of the American Southwest are admired by even 2 ，what makes the adobe dwellings admirable is their 3 “air condition”a house without 4 (use)electric equipment.(able) to most modern of architects and engineers.In addition to their simple beauty
