softening annealing

例句：

1. 1. The material was softened by the heat before it could be used in a machine.
   材料在被加热之前不能用于机器。
2. 2. During the annealing process, the metal is heated and then cooled to reduce its hardness.
   在退火过程中，金属被加热然后冷却以减少其硬度。
3. 3. The steel was softened by the heat from the furnace before it could be shaped.
   钢铁在炉内加热后才能成型。