You can work your entire career
without knowing the difference between a gerund and a participle, and still be
successful. You can live your entire life without knowing the difference
between a metaphor and a simile, and still be happy.
But you can’t write on the job
without knowing the difference between a main clause and a dependent clause, and
still be effective.
Before I explain why this is so, it
might help if I defined some basic grammatical terms. A “clause,” for example,
is a string of words that contains a subject and a verb. Clauses come in two
varieties: “main” (or “independent”) and “dependent” (or “subordinate”). A
“main clause” forms a complete sentence and can stand on its own. A “dependent
clause,” on the other hand, must be attached in some way to a main clause.
OK so far? Here’s where things get a
Often the relationship between a main
clause and a dependent clause is indicated by the use of “which” or “that”
(relative pronouns) and by the presence or absence of that most terrifying of
punctuation marks: the comma.
Now, don’t panic. Don’t flip to the
comics or the sports page yet. Just remember that a comma is simply a mark
separating the parts of a sentence. Some parts need separating. Others don’t.
(Centuries ago, the comma looked like a slash or “/”; over time its size has
diminished, but its function is unchanged.)
Take this sentence as an example: “The proposal which the council approved recommended hiring teenagers from the
inner city.” Because the writer has not indicated how the dependent clause
relates to the main clause, the sentence is unclear.
Does it mean the proposal, which
happened to be approved by the council, recommended hiring inner city
teenagers? Or does it mean, of all the proposals considered by the council, the
one that recommended hiring inner city teenagers was approved?
If you’re having trouble hearing the
difference, try reading the sentence out loud. For the first meaning, read it
with pauses (which I’ll mark the old way): “The proposal / which the
council approved / recommended hiring teenagers from the inner city.” For the
second meaning, change “which” to “that” and read it without pauses: “The
proposal that the council approved recommended hiring teenagers from the inner
Now can you hear the two meanings?
Your job as a writer is to ensure
that your reader understands which meaning you have in mind. You can accomplish
this by following these simple steps:
the main clause and the dependent clause. (In the example above, the main
clause is “The proposal . . . recommended hiring teenagers from the inner city,”
and the dependent clause is “. . . which the council approved . . .”).
if the dependent clause is “nonrestrictive” (that is, nonessential or merely
descriptive in meaning), or if it is “restrictive” (that is, essential to the
meaning of the sentence).
a nonrestrictive clause with “which” and mark it with commas.
a restrictive clause with “that” and do not mark it with commas.
Hint: If you can put parentheses around a dependent clause, it is, by definition, a
nonessential or nonrestrictive clause and therefore should be marked with commas
and introduced with “which.”
Now, if you made it this far, you
have survived an explanation of one of the most subtle, and most troubling,
rules of English grammar. But does it really matter? Does the reader care?
Only if your goal is to communicate
clearly and unambiguously. But here’s the irony: Even readers who don’t
respect this rule in their writing will understand your meaning more
precisely if you respect it in your writing.
It’s not fair, is it?