repeated melting

例句：

1. 1. The pot wasrepeatedly melted by the fire.
   锅被火反复加热。
2. 2. The material was repeatedly melted downto make new products.
   这种材料被反复熔炼以制造新产品。
3. 3. Theprocess of repeated meltingis essential for the production ofcertain metals.
   反复熔化的过程对于某些金属的生产过程至关重要。