roof joists laid to falls

例句：

1. 1.The builders laid the roof joists to support the weight of the roof.
   建筑工人铺设屋顶梁以支撑屋顶的重量。
2. 2. The house was built with high-quality roof joists for durability.
   这所房子使用了高质量的屋顶梁以确保耐用性。
3. 3. The roof joists need to be checked regularly to ensure they are not damaged.
   需要定期检查屋顶梁，确保它们没有损坏。