Grammar traps for writers

MISPLACED MODIFIERS (AKA Dangling Sentences or Dangling Participles)
Misplaced or dangling modifiers occur when phrases (usually involving the past or present verb particles, i.e. “ing” or “ed” ending verbs such as stalking or preyed) are not properly placed in a sentence in location to the words or phrases they are supposed to modify. Misplaced modifiers lead to illogical sentences that are difficult to follow (or plain ridiculous) and defy the rules of grammar.

What Are Modifiers in Grammar?
Adverbs, adjectives, or phrases can 'modify' other words or phrases in two ways. If they come before a noun phrase or verb they are said to premodify it; if they come after, they postmodify it. For example, in the sentence, 'The boy walked quickly', the adverb quickly postmodifies the past participle verb walked. In the sentence 'The girl softly sang', the adverb softly premodifies the verb sang.

How Do you Know a Sentence has a Misplaced Modifier?
Sentences that contain misplaced modifiers usually don't make sense if you scrutinize them carefully. For example:
Incorrect:    A magazine sat on the bench that Michele had read.
The modifier:    that Michele had read
The problem:    Had read, is placed closer to the noun bench than to the noun magazine. Michele did not read the bench. 
The solution:    A magazine that Michele had read sat on the bench.

The two most common types of modifier errors are misplaced modifiers and dangling modifiers. The example above is a misplaced modifier.

How do I Fix a Misplaced Modifier?
To fix misplaced modifiers, an editor will rewrite the sentence to place modifiers as close as possible to the words or phrases they should modify.
Incorrect:    The professor posted the notes for the students covered in class.
The modifier:    covered in class
The problem:    The modifier 'covered in class' appears to modify the students. Because the students are not 'covered in class', this is a misplaced modifier.
The solution:    The professor posted the notes covered in class for the students. [Or even better, The professor posted the notes that the students had covered in class.]
 
What are Dangling Modifiers? 
Dangling modifiers, or dangling participles, occur with -ing modifiers (present participles). They dangle when they are not logically connected to the main part (and therefore the subject) of the sentence. To correct these grammar problems, editors need to either recast the sentence to state the subject first, state the subject right after the dangling modifier or add a subject to the dangling phrase.
 
Incorrect: Walking through the park, the grass tickled my feet.
The problem: Walking through the park is modifying the noun 'grass' because there is no other obvious subject; however, the grass cannot walk through the park. Therefore, this is a misplaced modifier.
The solution: The grass tickled my feet as I walked through the park.
Walking through the park, I noticed that the grass tickled my feet.

Other Mismodifiers an Editor Will Detect
Sometimes, use of the words 'with' and 'as well as' can inadvertetly modify other words. In such instances, these words need to be changed to other conjunctions or linking phrases. For example:
“The male is smaller than the female with more contrasting markings”.
This implies the male is smaller only than a particular female that has more contrasting markings, but that is not what the author wants to say! He means “The male is smaller than the female and has more contrasting markings [than she does]”. Whenever you see "with" used without a comma in front of it, check what it should be linking or relating to.

This problem can also occur with 'as well as'. Take, for instance:
Males are smaller than females, as well as juveniles.

In this case, it might still make sense if the author means that both females and juveniles are smaller than males, but what if he meant “Males, as well as juveniles, are smaller than females” and simply misplaced the quasi-coordinator 'as well as'. In the above instance, it would be better to use 'and juveniles' if he means 'Males are smaller than females and juveniles' or 'Males and juveniles are smaller than females' if the second meaning is correct. The first is made ambiguous by the use of as well when and would do perfectly well. 

How Editors Detect Dangling or Misplaced Modifiers…
•  Carefully examine any sentence that starts or ends with a participle phrase or clause.
•   Edit for meaning, not just for punctuation
 •  Assess sentences to see whether they could be better understood if they were slightly modified.
•   Make sure that the quasi-coordinators "with" and "as well as" are correctly used and do not cause ambiguity.

Wherever you see an “ing” or “ed” ending as the opening or closing clause, examine it carefully.