All but one of the following sentences demonstrate incorrect use of a preposition; revise as necessary.
1. She is about to dive in to the pool.
2. I fell onto the platform.
3. When we disagreed, they turned in to our enemies.
4. John handed the paper into his teacher.
5. Do you have to hang up on every word he says?
Answers and Explanations
Generally, use “(verb) in to (noun)” to indicate location and “(verb) into (noun)” to indicate movement; the same rule applies to “on to” and “onto.”
Original: She is about to dive in to the pool.
Correct : She is about to dive into the pool.
One can dive in a pool (this wording refers to one’s location) or dive into a pool (this wording refers to one’s movement), but “dive in to a pool” has redundant prepositions.
Original: I fell onto the platform.
Correct : I fell onto the platform.
This sentence was originally correct.
Original: When we disagreed, they turned in to our enemies.
Correct : When we disagreed, they turned into our enemies.
The phrase “turn in” refers to an action involving a turn, but to turn into is to change or transform. (“Turned in” remains open in the sentence “They turned us in to our enemies,” in the sense of a betrayal.)
Original: John handed the paper into his teacher.
Correct : John handed the paper in to his teacher.
This sentence describes the action of delivering or submitting something, for which the idiom is “hand in,” so to should be separate from in.
Original: Do you have to hang up on every word he says?
Correct : Do you have to hang on every word he says?
Upon is technically correct but unnecessary in this idiomatic reference to someone giving undue attention to another’s comments — on is sufficient — but upon should be treated as two words only if the context alludes to someone ending a phone call abruptly: “Don’t hang up on me!”