plain metal的用法和樣例：
例句
- She was holding a teaspoon in her two hands, pressing her thumbs against it as if measuring her strength against the base metal.
她雙手拿著一個茶匙，用拇指使勁按著它，好象同這塊普通金屬較量力氣似的。 - Compared to ordinary metal armor, scale armor makes it a lot easier for warriors to move, significantly enhancing the mobility of the entire army.
與普通金屬鎧甲相比，魚鱗鎧甲能使武士行動更加自如，進而極大地增加了整個軍隊的機動性。
