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 little tricky.
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
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 city.”
Now can you hear the two
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:
1. Identify 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 . . .”).
2. Determine 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).
3. Introduce a
nonrestrictive clause with “which” and mark it with commas.
4. Introduce 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
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?