A reader wants to know “if there is a rule for the proper placement of an adverb in sentence structure.”
The general rule with adverbs is to place the adverb as close as possible to the word being modified. Most adverbs can go in one of three positions in a sentence.
First position (before the subject)
Cautiously, she opened the door.
Second position (before the main verb)
She cautiously opened the door.
Third position (after the verb or after the verb and its direct object or clause)
She opened the door cautiously.
Sometimes the position of the adverb doesn’t affect the meaning of the sentence, although it can contribute to a stylistic effect. For example, with cautiously in the above examples, placing the word first seems to suggest a dread of something that may be on the other side of the door.
With some adverbs, position affects meaning.
Take this example from the Chicago Manual of Style:
[The] marathoners submitted their applications to compete immediately.
Did the marathoners hit the trail as soon as they submitted their applications? Or did they submit their applications in a timely manner, in order to be eligible to compete? Placing the adverb next to the verb submitted eliminates ambiguity:
The marathoners immediately submitted their applications to compete.
Adverbs with Intransitive verbs
Adverbs generally follow an intransitive verb (a verb that does not have an object).
The children laughed uproariously.
The audience applauded wildly.
The accidents occurred intermittently.
Some exceptions are always, never, often, generally, rarely, and seldom. They can precede an intransitive verb:
He never laughs at my jokes.
His parents seldom agree.
Adverbs with Linking Verbs
Adverbs can follow a linking verb: The king is always angry.
Adverbs can follow the complement of a linking verb: The old man seems confused sometimes.
The important thing to remember about linking verbs and adverbs is, never try to use an adverb as the complement!
INCORRECT: Charlie feels badly.
CORRECT: Charlie feels bad.
Note: If Charlie has a disability that interferes with his sense of touch, then yes, he could be said to “feel badly.”
Adverbs with Transitive Verbs
Adverbs never go between a transitive verb and its object.
INCORRECT: He climbed determinedly the rock face.
CORRECT: He determinedly climbed the rock face.
Adverbs with Compound Verbs
When a verb is compound (has one or more helping verbs) the writer must decide where to put the adverb.
With one helping verb, place the adverb between the helping verb and the main verb.
I will gladly give you a ride.
The dog was secretly burying its toys in the garden.
With two helping verbs, place the adverb in one of two positions.
1. If the adverb modifies the entire thought expressed by the sentence, place it after the first helping verb:
They will certainly have read your submission by Thursday.
2. If the adverb is strongly modifying the main verb, place it directly in front of the main verb:
The boy’s behavior has been repeatedly reprimanded.
The reader who posed the question about adverb placement asked about four sentences in particular:
Managers often give employees feedback to help them improve their skills.
Managers give employees feedback often to help them improve their skills.
The first sentence places often next to the verb give, making it clear that the feedback is given frequently. Placing often in front of the infinitive to help in the second sentence suggests that the infinitive phrase is being modified.
We are limited to only storing five vehicles at this location.
We are limited to storing only five vehicles at this location.
With the adverb in front of storing, the sentence suggests that “We” can store five vehicles, but not other types of property. The second sentence makes it clear that a limited number of vehicles may be stored.
NOTE: Only is the trickiest adverb of all.