working time of closed section

例句：

1. 1. The engineer inspected the closed section to ensure it was properly sealed.
   工程师检查了封闭区域，确保其密封得当。
2. 2.The construction crew worked tirelessly to close the closed section and start the demolition.
   施工队不辞辛劳地工作，以封闭该区域并开始拆除工作。
3. 3. The scientists carefully sealed the closed section to prevent any contamination from entering.
   科学家们小心翼翼地封闭了封闭区域，以防止任何污染物进入。