We often use the verb " purchase" for when legal documents are involved, such as in: The government purchased a new contract for 1,000 airplanes.

当涉及法律文件时，我们通常使用purchase，例如：政府采购了1000架新飞机。

The government purchases rides on those vehicles a bit like buying a seat on a plane.

政府购买这些车辆的行程有点像购买飞机座位。

A man named Samuel Ellis purchased or bought this island in 1770, but the U.S. government purchased it from him in 1808.

一个名叫塞缪尔·埃利斯的人在 1770 年购买或买下了这个岛屿，但美国政府在 1808 年从他手中购买了它。