I came across three verb + on phrases in today’s New York Times article written by Maureen Dowd and titled “Stripped off Dignity”; it dealt with unpleasant airport pat-down practices.
In the following paragraph, I find the phrases “Keep jacket on,” “Hang on to unfinished bottle,” and “Leave shoes on.” It appears to me all these “keep on,” “hang on” and “Leave on” simply mean “keep on.” It may seem a silly question to you, native English speakers, but I’m curious to know the exact difference in meaning between the above three phrases, and to also understand why does "leaving" shoes “on” means to keep wearing shoes?
John Pistole, the T.S.A. chief, said they are trying to move past a “one-size-fits-all” program and implement a “risk-based, intelligence-driven process” by the end of the year that would have more refined targeting. If passengers are willing to share the same information they give to airline frequent-flier programs, he said, maybe someday they will be able to keep their jacket on and their laptop in their briefcase and hang on to that unfinished bottle of water.” “I’d like to get to the point,” he said wistfully, “where most people could leave their shoes on.