Sentence examples for this may once from inspiring English sources

This may once have been true, but certainly isn't now.

This may once have been on the verso of the board on which it is painted but unfortunately, the painting has been glued to another wooden support, so this information cannot be checked.

This may once again suggest that warning signals were followed.

This may once again be associated with denture-wearing which was approximately three times more common in type 2 diabetic males (47%) compared to females (16.6%) with T2D.

Furthermore, since dystocia may be related to fetal macrosomia, and fetal distress may be related to various other conditions (including diabetes, hypertension, and collagen vascular disease), this may once again have introduced potential redundancies into the regression.

This idea may once have had validity.

This city may once have been Baluchi, but now it is also very much Pashtun.

But if it fails, this nation may once again be plunged into a nasty conflict in which neither side seems able to win a decisive military victory but which may inflame ethnic tensions to the point of civil war.

This alliance may once have had something to do with ideas, but it has become mainly a corrupt political machine, and America will be a better place if that machine breaks down.

Nasa will attempt to land its one-tonne Curiosity rover on the Red Planet to study the possibility that this world may once have hosted microbial life.

This atmosphere may once have been even thicker, with much of it being boiled off into space over the eons by the red dwarf's radiation.