The phrase "has been a central theme" is grammatically correct and can be used in written English.
It is typically used to describe a recurring or prominent idea in a piece of literature or discourse. Example: Throughout the novel, the struggle between good and evil has been a central theme, with each character representing opposing forces.
Sixty-four percent of voters polled said Mr. McCain, 72, was well-prepared for the presidency, which has been a central theme of his campaign.
In keeping with what has been a central theme of his 2006 candidacy, Mr. Booker said that stopping school violence would be his first priority.
Their conclusions, while familiar to a small core of social sciences scholars, are now catching the attention of a broader audience, in part because income inequality has been a central theme this election season.
The gun-trafficking allegations strike at the heart of one of the New York Police Department's most hard-fought and robust initiatives, and one that has been a central theme of the administration of Mayor Michael R. Bloomberg: getting guns off the street of New York City.
With local elections in December and a new presidential contest due in 2016, when Mr Ma will have to stand down, the DPP seems to think it has the KMT on the run.Improving relations with China has been a central theme of Mr Ma's presidency since he took office in 2008.
The gun-trafficking accusations strike at the heart of one of the Police Department's most hard-fought and robust initiatives, and one that has been a central theme of the administration of Mayor Michael R. Bloomberg: getting guns off the city's streets.
Development of high-performance cost-effective electrocatalyts that can replace Pt catalyst have been a central theme in polymer electrolyte membrane fuel cells (PEMFCs) including direct methanol fuel cells (DMFCs).
Since the 1980s, the term has been a central or major theme of more than 2000 scientific articles.
Black magic has been a disconcertingly central theme of western art for centuries.
Mars has also been a central theme in radio, television, and film, perhaps the most notorious case being Orson Welles's radio-play production of H.G. Wells's novel War of the Worlds, which convinced thousands of unwitting listeners on the evening of Oct. 30, 1938, that beings from Mars were invading Earth.
Maternal ambivalence has long been a central theme of her writing – "I thought I was going to be the Philip Roth of maternal ambivalence," she says, "I thought I was going to write about the same thing until I died or decided to quit writing" – and if her critics have focused on the ambivalence side of the equation, it's clear she's consumed by family life.
