例句與造句

1. Polished stone tools continued to be used due to their abundance compared with the less common metals ( especially tin ).
2. These combined factors made possible the development of metal smelting, with copper and later bronze, an alloy of tin and copper, being the materials of choice, although polished stone tools continued to be used for a considerable time owing to their abundance compared with the less common metals ( especially tin ).
3. It's difficult to find less common metal in a sentence. 用less common metal造句挺難的