上部结构用英语怎么说？

上部结构

例句

• Manufacturers of the early 1900 s were using steel pipe, angle or channel for the greenhouse superstructures. 二十世纪初期制造商们就已用钢管 、 角铁以及槽钢之类的材料建造温室的上部结构.
• Cypress and redwood are seldom used in the superstructure of commercial greenhouses. 扁柏和美州红松很少用于商用温室的上部结构.
• A slender superstructure was dictated with gently sloping approaches rather than staircases. 细长的上部结构,带有微缓斜坡接坡,比布置阶梯为优.