A specific part of a larger area of study or work.
In physics, there are many subfields, including quantum mechanics.
在物理學中,有許多子領域,包括量子力學。
A section of land within a larger area, used for a particular purpose.
The farmer divided his land into subfields to grow different types of crops.
農民把他的土地分成幾個子田地,以種植不同類型的作物。