prestressed reinforced concrete

例句：

1. 1. The beam is prestressed to support the weight of the roof.
   这个梁是预应力的，用来支撑屋顶的重量。
2. 2.The concrete beam is prestressed to prevent it from cracking.
   混凝土梁是预应力的，以防止它开裂。
3. 3.The steel cables are prestressed to hold the structure together.
   这些钢缆是预应力的，用来保持结构的整体。