Rules for Usage:
PREPOSITIONS THAT ESTABLISH MOTION AND DIRECTION
The prepositions of motion “to,” “toward,” “in,” and “into.” These four prepositions link the verbs of movement—“move,” “go,” “transfer,” “walk,” “run,” “swim,” “ride,” “drive,” “fly,” “travel,” and many more—to their object destination. All of these verbs, except “transfer,” can take both “to” and “toward.”
We must keep in mind, however, that “to” is used to convey the idea of movement toward a specific destination, while “toward” is used to convey movement in a general direction that may not reach a specific destination:
“Please take me to the bus station.”
(The speaker obligates the listener to specifically take him to a particular place.)
“The speedboat headed toward the harbor.”
(The speaker indicates only a movement in a general direction.)
We can actually interchange “into” and “in” more or less freely when used with verbs of motion. There are exceptions, though. We can only use “in” (or “inside”) when the preposition is the last word in the sentence or occurs right before an adverbial of time (“today,” “tomorrow”), manner (“quickly,” “hurriedly”) or frequency (“once,” “twice”).
Examples: “The woman went into the manager’s office.” “The woman went in twice.” “The woman went in.” “The new tenants moved into the apartment yesterday” “The new tenants moved in hurriedly.” “The new tenants moved in.”
We can also use “into” as the last word in a question: “What sort of trouble have you gotten yourself into?” But we should use “in” if the question is said in this form: “What sort of trouble are you in?”
“In/into” also has two unique uses with the verb “move.” The first is when “move in” is followed by a clause indicating purpose or motive: “The hunters moved in for the kill.” “The soldiers moved in for the attack.” In both examples, “in” is part of the verb phrase, so we cannot use “into.”
The second case is when we use “into” with “move” to convey the idea of simple movement: “The firemen moved into the burning building.”
The prepositions of direction “to,” “onto,” and “into.” These prepositions correspond to the common prepositions of location: “to” for “at,” “onto” for “on,” and “into” for “in.” Each is defined by the same space relations of point, line, surface, or area as in the prepositions of location.
“To,” the basic directional preposition, signifies orientation toward a goal. If that goal is physical, like a specific destination, “to” conveys the idea of movement in the direction of that goal: “The troops returned to their base.”
“Toward,” of course, also works as a directional preposition, and means about the same thing as the directional preposition “to.” If the goal is not a physical place, as in an action, “to” simply puts the verb in the infinitive form to express a particular purpose: “She sings to earn extra money.” “She cut her hair to show her displeasure.”
The directional prepositions “onto” and “into” are, as we know, compounds formed by “to” with corresponding prepositions of location: on + to = onto, to signify movement toward a surface, and in + to = into, to signify movement inside a finite three-dimensional space or volume.
When used with many verbs of motion, however, “on” and “in” already have a directional meaning. We therefore can freely use them instead of “onto” and “into.” Note that “on” and “onto” work equally well in the following sentences: “The cats fell on [onto] the floor.” “The whales washed up onto [on] the beach.” “The girl jumped into [in] the river.”
You will notice, however, that always, the compound locational prepositions “onto” and “into” convey the consummation of an action, while the simple locational prepositions “on” and “in” indicate the subject’s end-position as a result of the action.
Let’s look at some examples.
Consummation of action: “The boy fell onto [to] the ground.” “The sailor dived into [to] the pool.”
Position of subject: “The boy is on the ground.” “The sailor is in the pool.”
Now we discover something interesting: directional prepositions actually serve to convey the idea of cause, while locational prepositions serve to convey the idea of effect. This, in fact, is as near a rule of thumb as we can get in dealing with these two kinds of prepositions.
We cannot leave this subject, of course, without discussing “at” as a preposition of motion and direction. Being the least specific of the prepositions in space orientation, we can use “at” in a good number of ways.
To mark a verb of motion directed towards a point: “She arrived at the airport late.” “The marksman aimed atthe hostage-taker with precision.”
To indicate direction: “The man leaped at the thief to subdue him.” “She jumped at me without warning.”