(When writing works like math …)
A modifier is a word or phrase that describes a noun. Modifiers are misplaced when they aren’t positioned immediately before or after the noun they refer to. (Just as in math, sequence matters in writing.)
Incorrect: Upon entering the room, the picture offended Larry.
(In this example, Larry is the one who enters the room … not the picture! The clause “upon entering the room” refers to Larry and should be placed next to him so the reader is not confused.)
Correct: Upon entering the room, Larry was offended by the picture.
Incorrect: Flying through the air, the girl was hit by the ball.
Correct: Flying through the air, the ball hit the girl.
The girl was hit by the ball that flew through the air.