by Abdulla Thu Dec 11, 2008 7:43 pm
check this
Which vs. That
Property of the Regent University Writing Center Material is borrowed from A Writer’s Reference by Diana Hacker, 5th edition, pp. 239-241.
". . . which . . ." or ",which . . ."
"Which" is used in both subordinate clauses and nonessential clauses. Within subordinate clauses,
"which" is used in this format: Sentence 1 + which + sentence 2. With nonessential clauses, "which" is
used as follows: Sentence + comma + which + extra information describing the noun/pronoun.
Example 1 (subordinate clause):
Elizabeth set the alarm clock which she thought was the loudest.
In this example, the first sentence "Elizabeth set the alarm clock" is joined to the second sentence "she
thought [it] was the loudest." The second sentence does have both a subject and verb, so it is
subordination. (Certain subordinate words require slight adjustments to the second sentence. In this case,
the pronoun "it" was removed when "which" was added because the second sentence becomes more
dependent upon the first.)
Example 2 (nonessential clause):
Elizabeth bought the loudest alarm clock, which was also the most expensive on the shelf.
In this example, the main message and meaning of the sentence is "Elizabeth bought the loudest alarm
clock." The phrase "which was also the most expensive on the shelf" is not a sentence"”it is just a phrase
that describes the loudest clock. It is nonessential information, however, because if the information was
removed, the main message and meaning of the sentence would not be changed.
". . . that . . ."
"That" is used in both subordinate clauses and essential clauses. Within subordinate clauses, "that" is
used in this format: Sentence 1 + that + sentence 2. Within essential clauses, "that" is used as follows:
Sentence + that + critical or necessary information describing the noun or pronoun.
Example 1 (subordinate clause):
Elizabeth needs to buy an alarm clock that she can depend upon.
In this example, the first sentence "Elizabeth needs to buy an alarm clock" is joined to the second
sentence "she can depend upon [it]." Again, the second sentence has both a subject and verb, so it is
subordination. (The slight adjustment"”removing the extra "it""”helps to make the sentence smoother.)
Example 2 (essential clause):
Elizabeth needs to buy an alarm clock that is loud enough to wake her up.
In this example, the information "Elizabeth needs to buy an alarm clock" does not convey the entire
meaning of the sentence. Elizabeth does not need to buy just any alarm clock. She needs to buy an alarm
clock "that is loud enough to wake her up." In this instance, the information following "that" is not a
sentence"”it is a phrase that provides information that is critical to the meaning of the sentence. If the
information was left out, the sentence could still work and be grammatically correct, but the meaning
would be altered. This makes it an essential clause. :D