When there is a modifier in the form of a word, phrase, or clause in a sentence, there must be something for it to modify. If the thing to be modified is not present in the sentence, the modifier is said to dangle as it modifies nothing. However, it will be wrongly modifying something else close to it. Such a modifier is called a dangling modifier. A sentence having a dangling modifier is confusing, as it doesn’t make sense also. To make correction, put in the word that has been left out of the sentence for the modifier to modify also.
A modifier often occurs at the beginning of a sentence. To avoid a dangling modifier, the subject to be modified is placed as close to the modifier as it can be. The closest it can be is immediately after the modifier, and that is at the beginning of the second clause.
For an example, look at this sentence:
Looking at the sea, a boat approaching shore was noticed.
In this sentence, the first clause looking at the sea is a modifier. It should be modifying the subject of the sentence. But the subject is not around to be seen. The subject should be at the start of the second clause for the modifying clause to modify also. Instead, the subject’s place is taken by a boat: a boat approaching shore was noticed. There has to be a subject who was looking at the sea. But a boat is not the subject as a boat cannot see, and yet it is modified, thus giving rise to a dangling modifier. To correct it, insert a subject in the sentence for the modifying clause to modify also. The subject can be I, my father, or Mr Brown depending who it is.
Correct: Looking at the sea, I noticed a boat approaching shore.
Dangling modifier: Having seen the movie once, there is no reason to see it again.
Correct: Having seen the movie once, we have no reason to see it again.
Dangling modifier: Bitten by a snake, the fear was that the snake could be poisonous.
Correct: Bitten by a snake, he feared the snake could be poisonous.
Dangling modifier: While lying under a tree, a bee stung his left ear.
Correct: While John was lying under a tree, a bee stung his left ear.
Dangling modifier: The weather was fine; swimming and splashing sea water at each other.
Correct: The weather was fine; we swam and splashed sea water at each other.
Dangling modifiers often happen to participial phrases, prepositional phrases, and infinitive phrases.
Incorrect: Arriving at the restaurant, a good dinner was decided.
(Arriving at the restaurant is a participial phrase acting as a modifier. Did a good dinner arrive at the restaurant? It couldn’t be. It’s somebody, for example, we, who arrived at the restaurant also. But the somebody or we is not found in the sentence. This makes the modifying participial phrase a dangling modifier.)
Correct: Arriving at the restaurant, we decided on a good dinner.
(To correct the sentence, a right subject is needed in the main clause. The subject we is used.)
Incorrect: As a baby, my mother would often rock me to sleep in her arms.
(As a baby is a prepositional phrase. It is not likely that it modifies the noun mother next to it, as the baby is not the mother also. Hence, it dangles with no word to modify.)
Correct: When I was a baby, my mother would often rock me to sleep in her arms.
(The prepositional phrase is now changed to a dependent clause, and together with the main clause form a complete sentence.)
Incorrect: To pass the exam, studying hard was needed.
(To pass the exam is an infinitive phrase. A person is needed to pass the exam. The person is the subject which is missing, making the modifying infinitive phrase dangling with nothing to modify.)
Correct: To pass the exam, I needed to study hard.
(The sentence is now correct as a subject I is introduced for the infinitive phrase to modify.)