短语词组短语hollow electron beam [电子]空心电子束;中空电子束Hollow Flange Beam 空翼缘梁hollow no beam roof 空心无梁楼盖hollow girder beam 空心板梁hollow w beam 空心梁prestressed hollow plate beam 先张空心板梁hollow arbor beam 管梁hollow board beam 空心板梁 返回 hollow beam