Sentence examples for a key reason is from inspiring English sources

A key reason is European politics.

A key reason is cost.

A key reason is that it works better aesthetically.

A key reason is the connection between selection and moral hazard in star hospital use.

A key reason is that Asians living in Britain maintain an immigrant mentality towards sport.

A key reason is that while foreign investment surged, domestic investment in Mexico dipped.

A key reason was fear, Dougan and others said.

A key reason was "a thinning of an informed, engaged, independent centre of our polity".

A key reason was that individuals' engagement varied highly significantly during the lecture.

According to Jeffrey Clemens, an economist at the Stanford Institute for Economic Policy Research, a key reason was New York's aggressive expansion of Medicaid to cover the "medically needy," which drew in more relatively unhealthy New Yorkers.

A key reason was Erdogan's provocative insistence on transforming the presidency from a largely ceremonial position to a strong executive post.