Drop hammer: a machine consisting of an anvil or base aligned with a hammer that is raised and then dropped on molten metal used to forge or stamp the metal resting on the anvil.
落锤：由钻或底座及与之对齐的锤组成的机器，锤被举起后落在融化金属上用于锻造或冲压放在砧板上的金属。
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If you already have a postage stamp for the letter, you can just drop it into the mailbox at the street corner.