题目解析:
选项A错误,新的建筑材料并不难找;选项B正确,文本“Today technology has progressed to the point where it is possible to invent new building materials to suit the type of structure desired".选项C错误,目前已经有很多材料,这三样是以前的基本建材。选项D错误,第五句话中有提到“…have made it possible to enclose space with much greater ease and speed..."并没有说明以前不能造大空间房子。