in some sphere
in a sphere

But no: they were still lost in their individual spheres of play.

Only, if you move in different spheres, that does not happen.

Not that all was well in the sphere of order and crime.

All of this would serve him well in the public sphere.

We have not talked to any of the countries in the sphere about this yet.

No progress has been made in the sphere of democratic rights, either.

He didn't seem to be in his proper sphere at all.

At this point, he isn't even in the same sphere.

He suggested that the world would be a better place if women were involved in the political sphere.

He became active again in politics and the public sphere.