skip navigation

After / Before -ing

Reducing time-relative clauses

A smelly skunk

 

 

Reducing time-related (temporal) clauses

FULL CLAUSE

Before, after, while, when, and since relate the timing of two events. They are referred to by a number terms depending on the grammar system. See "adverbiall clauses" or "temporal location expressions" in Grammar Notes below.

MAIN CLAUSE ADJUNCT CLAUSE

Jack saw a skunk
look up 

while he was walking.
move overlook up 
(same time)

Jack stopped

when he spotted it. (immediately after)

Jack waited a short time

before he continued on. (earlier)

Jack still smelled the skunk

after he passed that area. (later)

Jack has been taking a new way home

since he saw a skunk there. (from that time to now)

REDUCED CLAUSE

The joined clause may be reduced to a modifying clause if the subjects of both clauses refer to the same person or thing.  The verb in the modifying clause takes the form of a gerund (gerund-participle nonfinite clause).

MAIN CLAUSE MODIFYING CLAUSE

Jack saw a skunk

while walking home.
look up
modifies Jack

Jack stopped

when spotting it.

Jack waited a while

before continuing on.

Jack could still smell the skunk

after passing through the area.

Jack has been taking a different way home

since seeing a skunk there.

 

spot (v.) – notice, identify, recognize

Complement:  an element that is required by the subject and verb, for example, an object, indirect object, predicative complement.  John saw the skunk.

Adjunct: an optional element such as a modifier, for example, Adj,  Adv, a subordinate clause, a supplemental clause. John saw a skunk while walking.

See Grammar Notes for terms.

 

 

 

 

 

 

Reduced Clauses

Initial vs. Final Position

 

 

 

Initial vs. final position

INITIAL

Use a comma A temporal clause—while, when, after, before—clause may be placed before and next to the noun that it modifies. A comma separates the clauses.

MAIN CLAUSE ADJUNCT CLAUSE

While walking home,

Jack came across an animal.

When spotting the animal,

he stopped.

Upon seeing a skunk,

he turned around.

Before continuing on,

he waited a short time.

After passing the area,

he could till smell the skunk.

Since seeing a skunk there,

he has been taking a new way home.

FINAL

no commaA temporal clause—while, when, after, before—clause may also be placed after the main clause.  No comma separates the two clauses.

MAIN CLAUSE MODIFYING CLAUSE

Jack came across an animal

while walking home.

He stopped

when spotting the animal.

He stopped

upon seeing a skunk.

He waited a short time

before continuing on.

He could still smell the skunk

after passing the area.

He has been taking a different way home

since seeing a skunk there.

 

came across – met my chance
upon – when

 

 

 

 

 

 

Reduced Clauses

Omitting When, While or Upon

dog coming indoors
 

 

Omitting an initial when or while clause

WHEN / WHILE INCLUDED

A when or while modifying clause is placed directly before the subject noun (the person doing the action) in the main clause.

MODIFYING CLAUSE MAIN CLAUSE

 When arriving home
   modifies Jack
   modifies Jack  

Jack greets his dog.    

While getting a drink of water

Jack watches his dog.    

Upon bringing in his dog

Jack wipes its paws.    

WHEN / WHILE OMITTED

While or when can be omitted from a modifying clause. The same-time relationship will be understood from the context.

WHEN / WHILE OMITTED MAIN CLAUSE

Arriving home,
   modifying clause
   modifies Jack

Jack greets his dog.

 

Getting a drink of water,

Jack watches his dog 

Bringing in his dog,

Jack wipes its paws.    

 

*Yellow highlighting indicates example of incorrect usage.
(Upon means when.)
Related page Dependent / Independent Clause

 

 

 

Omitting a final when or while clause

SUBJECT MODIFIER

A when, while or upon modifying clause placed after the main clause is still understood as modifying the subject noun.

SUBJECT OF MAIN CLAUSE MODIFYING CLAUSE

Jack greets his dog

when arriving home.
(modifies Jack)

Jack watches his dog

while getting a drink of water.
(modifies Jack)

Jack wipes his feet

upon entering the house.  (modifies Jack)

OBJECT MODIFIER

Removing when, while or upon from the modifying may result in confusion.  Which noun is being modified?

WHEN / WHILE OMITTED SUBJ  / OBJ MODIFIER?

Jack greets his dog

arriving home.  (Jack or the dog?)

Jack watches his dog

*getting a drink of water.
(unclear modifier)

Jack wipes his feet

entering the house.
(modifies Jack)

 

*Better placement: When coming home, Jack greets his dog.  (Place modifier next to noun.) 

 

 

 

 

 

 

Reduced Clauses

Omitting After

door locked
 

 

Expressing an earlier time in a reduced clause

WHEN / WHILE INCLUDED

After is included in a reduced clause to express an earlier time frame than that of the main clause.

MODIFYING CLAUSE MAIN CLAUSE

After being burglarized,   

Anne is very cautious.

After closing the windows,   

Anne locked the front door.

After setting the alarm,

Anne locked the front door. 

REDUCED

After is omitted from a modifying clause if the earlier time is expressed in the form of the verb—a past participle.

AFTER OMITTED MAIN CLAUSE

Having been burglarized,   

Anne is very cautious.

Having closed the windows,

Anne locked the front door.

Having set the alarm,

Anne locked the front door.. 

 

burglarize (v.) – break in and steal from
cautious (adj.) – careful

 

 

 

 

 

 

Common Mistakes

Errors and Solutions

 

 

 

Error and Solution

ERROR

*Before taking a driving course, his father told him to be careful.

Who is taking the driving course? 

*Unfortunately, the ball hit Jack in the back of the head while running.  

Who was running – the ball or Jack? 

We stopped hearing the police siren

(Unclear – this means we were no longer hearing the sound.)

SOLUTION

Before the son took a driving course, his father told him to be careful.

The subjects of both clauses must be the same to use a modifying clause.

Unfortunately, the ball hit Jack in the back of the head while Jack was running. (Restate the subject.)

Unfortunately, Jack was hit  in the back of the head while [he was] running.

(Rephrase the sentence with Jack as the subject of the main clause.)  

We stopped when hearing the police siren.

We stopped when we heard the police siren.

 

*Yellow highlighting indicates example of incorrect usage.

 

 

 

 

 

 

Grammar Notes

Traditional and Linguistic Descriptions

 

 

 

"Adverbial Clauses" / "Temporal Location Expressions"

PAST GRAMMAR CURRENT GRAMMAR

Adverbial Clauses 

In traditional grammar while, when, before, after, an since are conjunctions which join an adverb clause to an independent clause. The term adverbial clause is used because the clause adds time-related information about the verb and answers the question When? This added-on structure is called a dependent clause because it can not stand alone as a sentence.

 

Swan (2009) refers to while, when, before, after, and since as conjunctions. (30.1)

Temporal Location Expressions 

In current linguistic analysis—while, when, before, after, and since —have been re-classified into the category of preposition. Each of these temporal expressions takes a finite clause or nonfinite clause as its complement.  

Preposition (PP) + finite clause—John saw a skunk while he was walking home.

Preposition (PP) + nonfinite clause—John saw a skunk while walking home. [gerund-pariciple]

Before or after additionally takes a noun phrase as its complement.

Preposition (PP) + noun (NP)—John smelled the skunk before the sighting. John saw the skunk before us.

(Note that a Preposition is not limited to a noun complement. In fact, it may take a number of structures as its complement. Prep Complements)

Azar & Hagen call these adverbial clauses or "time clauses" with no mention of a term for the connector. It is not clear whether while, when, before, after, and since are adverbs or conjunctions.   "A time clause begins with such words as when, before after, as soon as, until, and while and includes a subjects and a verb.  The time clause can come either at the beginning of the sentence or in the second part of the sentence…" (4-3, Adverb clauses 17-2; Reduction  18-1)

Huddleston & Pullum (2009) have re-assigned a large number of items previously analyzed as adverbs after, as, as soon as, before, once, since while, and when to the class of Preposition.  The preposition is the head of the prepositional phrase (PP) which can be complemented by a noun phrase or a clause with a subject and a verb, or a clause with a gerund-participle.  (612-7)
Also see " Nonfinite clauses as modifiers and supplements"  (1265-6)

Quirk & Greenbaum (1989) place while, when, before, after, and since in the class of conjunction.  They function as subordinators of adjunct clauses that express time-relationship. (8.53)
 

The structure is called an adjunct because it is not required by the verb to complete the sentence. It adds additional information.

Complement—John saw a skunk.  ["a skunk" is required to complete the verb]

Adjunct— John saw a skunk while we were walking.  [the prepositional phrase is an "add on", extra information]

 

 

Resources

 

 

 

 

 

 

Practice 1

Same-time Events

Counting Sheep
 

Shorten the clause to a modifying clause if possible. 

  1. Select the response from the list that best completes the sentence. 
  2. Compare your response to the feedback by clicking the "check" or "check 1-10" button.

 

1.

2.

3.

4.

5.

6.

7.

8.

9.


Note that no comma is used when the conjunction follows the main (independent clause.)

10.

 

 

 

 

 

 

 

Practice 2

Verb Forms in Modifying Clauses

a pulled muscle
 

Decide on the verb form that should be used in the reduced clause.

  1. Select the response from the list that best completes the sentence. 
  2. Compare your response to the feedback by clicking the "check" or "check 11-16" button.

 

11.

 
a pulled muscle (n.) – to injure a muscle by stretching it too much during physical activity

12.
stretching out

stretch out (v.) – extend muscles in body

13.


elliptical machine (n.) – a machine for exercising

14.

15.

16.


injure (v.) – hurt