be on to
Be aware of or have information about, as in They can't pull that trick again; we're on to them now. [Colloquial; second half of 1800s]
Discover something important or profitable, as in The researchers claim they are really on to something big. [Colloquial; mid-1900s]
Words nearby be on to
How to use be on to in a sentence
Just the hard-on before you shoot unarmed members of the public.'Babylon' Review: The Dumb Lives of Trigger-Happy Cops|Melissa Leon|January 9, 2015|DAILY BEAST
Three on-the-record stories from a family: a mother and her daughters who came from Phoenix.I Tried to Warn You About Sleazy Billionaire Jeffrey Epstein in 2003|Vicky Ward|January 7, 2015|DAILY BEAST
You just travel light with carry-on luggage, go to cities that you love, and get to hang out with all your friends.
It was a brick wall that we turned into the on-ramp of a highway.
Could the (thus far) timid trembling give way to a full-on, grand mal seizure?26 Earthquakes Later, Fracking’s Smoking Gun Is in Texas|James Joiner|January 7, 2015|DAILY BEAST
Each day she resolved, "To-morrow I will tell Felipe;" and when to-morrow came, she put it off again.Ramona|Helen Hunt Jackson
All the operations of her brain related themselves somehow to to-morrow afternoon.Hilda Lessways|Arnold Bennett
"Buy something for your wife that-is-to-be," he said to his grand-nephew, as he handed him the folded paper.The Pit Town Coronet, Volume I (of 3)|Charles James Wills
Something remote and ancient stirred in her, something that was not of herself To-day, something half primitive, half barbaric.The Wave|Algernon Blackwood
To-day I'm more dead than alive, as we had a lesson from him yesterday that lasted four hours.Music-Study in Germany|Amy Fay