Lead is one of the common metals. Being very soft, it is easily made to assume any shape.

铅是最常见的金属之一。由于它很软，所以很容易被塑造成各种形状。

Chris names three other kinds of more common metals, metals that are less expensive.

克里斯列举了另外三种更常见的金属， 它们更便宜。

It's more practical to use aluminum for aircraft building it's cheap, strong, and machinable while titanium is expensive and isn't easy to get despite being the seventh most common metal on Earth.

使用铝来制造飞机更为实用，因为它便宜、坚固且易于加工， 而钛则昂贵且不易获得， 尽管它是地球上第七种最常见的金属。