谁帮我翻译这一段落? Some contractors employ a system of erection in which the bottom plates are completed, the top course is erected on the bottom plates, the roof framing and sheeting are completed and a number of jacks are then assembled around the structure. By means of these jacks, the completed top course together with the roof framing and sheeting is lifted to a height sufficient to insert the next lower course. The jacking method and the supporting of the partly erected shell shall have no adverse effect on the roundness of the shell. The welding is completed at each stage of lift until all courses of the shell plates have been inserted and the finished height is reached. The final operation is the welding of the bottom course to the bottom plates. See Appendix 1. 查看更多2个回答 . 3人已关注