open trench短语¹⁸⁰⁰⁹⁸⁺¹ 基本例句 明沟 Therefore the general construction process scheme is worked out as follows: open trench drainage, work site dried in the sun, conventional butt welding, and pipe laid down into trench. 经过调研和反复现场勘察，确定的总体施工方案为：挖明沟排水，作业带晾晒，正常组对焊接，沉管下沟。 dictall