Which or That?
By Nancy L. Tuten, PhD, and Gayle R. Swanson, PhD
While both which and that can be used in other
constructions, the confusion usually arises when they are being
used as relative pronouns to introduce adjective (or relative)
clauses. In the examples below, we have bracketed the adjective
clauses. (Remember that a clause is simply a group of words
containing a subject and a verb):
[that has a red door and green shutters] needs painting.
[which has a red door and green shutters], needs
classrooms [that were painted over the summer] are
bright and cheerful.
classrooms, [which were painted over the summer], are
bright and cheerful.
all four cases, the adjective clause tells us something about
either the house or the classrooms, but the choice of which
or that changes the way we should read each sentence.
In the first sentence, the use of that suggests that we
own more than one house and therefore must explain to you that
we are talking about a particular house of ours--the one with a
red door and green shutters. We cannot leave out that adjective
clause because it is essential to your understanding of the
sentence; that is, you wouldn't know which one of our houses
needs the paint job without that adjective clause.
The second sentence tells you that we own only one house and we
are simply telling you--in case you want to know--that it
happens to have a red door and green shutters. We could leave
out the information in that adjective clause and the sentence
would still make sense.
The third sentence, because it uses that to launch its adjective
clause, tells us that only SOME of the classrooms were painted
over the summer. If we omitted the clause "that were painted
over the summer," we would be left with "The classrooms are
bright and cheerful," a statement that would not be accurate
since it would imply that ALL the classrooms are bright and
cheerful. In this sentence, therefore, the adjective clause is
essential to the meaning of the sentence.
We call the adjective clauses in sentences one and three
restrictive because they restrict--or limit--the meaning of the
nouns they modify. In the case of sentence three, they tell us
that we are talking ONLY about the classrooms that were painted
over the summer--not the others.
The which clause in the fourth sentence is what we call a
nonessential--or nonrestrictive--clause. Since that sentence
intends to tell us that ALL the classrooms were painted, the
information in the adjective clause is not essential. The
sentence would be clear even if the clause were omitted.
The rule of thumb, then, is that which clauses are
nonrestrictive (nonessential) while that clauses are
restrictive (essential). Nonrestrictive clauses and phrases are
set off from the rest of a sentence by a pair of commas (as in
our examples above) or by a single comma if they come at the end
of the sentence. (Example: "I took a vacation day on my
birthday, which happened to fall on a Monday this year.")
Merriam-Webster's Collegiate Dictionary (10th edition),
regarded by most writers as the authority on such matters, tells
us that it is now common for which to be used with either
kind of clause, while that must be used only for
restrictive clauses. In fact, though, careful writers continue
to make the distinction we describe above. Attorneys are taught
to use which for nonrestrictive clauses and that
for restrictive clauses so as not to cause a misreading in legal
documents. It seems just as important that we work to avoid
misreadings in all writing, not only in situations when a legal
ruling might be at stake.
Which pronoun--which or that--belongs in each
gave Maria a study guide for material ________ was going
to be on the test.
gave Maria notes from chapters 3 through 7 _________
were going to be on the test.
Sarah took their children on every vacation _________
they took to the coast.
teachers gave awards to all paintings ________ showed
gave Maria a study guide for material *that* was going
to be on the test. [To say simply "Carlos gave Maria a
study guide for material" would not be complete
information. We need the adjective clause to tell us
which material, in particular. Since the information is,
therefore, essential, we use that and no comma.]
gave Maria notes from chapters 3 through 7, *which* were
going to be on the test. [The fact that chapters 3
through 7 were going to be on the test is not essential
to our understanding exactly which notes Carlos gave
Maria, so we use a comma and which.]
Sarah took their children on every vacation *that* they
took to the coast. [If we said simply "Mark and Sarah
took their children on every vacation," we would be
inaccurate. The information in the adjective clause is
essential to our understanding that the children went on
certain vacations and not others. Therefore, we use
that and no comma.]
teachers gave awards to all paintings that showed
originality. [To say simply "The teachers gave awards to
all paintings" would be inaccurate. The information in
the adjective clause is, therefore, essential to the
meaning of the sentence, so we use that and no
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