The phrase "a common subject of" is correct and usable in written English.
It can be used when discussing topics that are frequently addressed or explored in a particular context, such as literature, research, or conversation.
Example: "Climate change is a common subject of debate among scientists and policymakers."
Alternatives: "a frequent topic of" or "a popular theme in".
Where to find eggs is a common subject of discussion.
Watching porn was a common subject of discussion.
Making the issue a common subject of public conversation will aid this transformation.
Local government corruption is a common subject of attack by local journalists and internet surfers.
Hispanics were a common subject of conversation at both conventions last week.
Not all of Fleischmann's children shared his entrepreneurial drive, and this was a common subject of conversation in the Holmes household.
Mr. Tress has taken many photographs of children, frequently showing them sleeping or in states of reverie, a common subject for artists with a Surrealist bent.
In Copernicus's period, astrology and astronomy were considered subdivisions of a common subject called the "science of the stars," whose main aim was to provide a description of the arrangement of the heavens as well as the theoretical tools and tables of motions that would permit accurate construction of horoscopes and annual prognostications.
A common subject in the works of the many South African authors writing in English during the 20th century is the racial segregation, codified as apartheid in 1948, that dominated the country until the early 1990s.
When experts from different fields work together on a common subject within the boundaries of their own discipline, they are said to adopt a multidisciplinary approach.
However, sometimes, students are mystified due the existence of different styles of presentations, definitions, terminologies and examples of a common subject in those sources.
