The good news is that we have a very simple approach to determining the difference between “which” and “that” and by reading just three short paragraphs you can banish this particular grammar hangup for good.
The difference between which and that involves two simple rules:
- The word “that” should be used before a restrictive clause.
- The word “which” before any other clause (a nonrestrictive clause).
That’s pretty much it. Simple really.
Great. But what’s a restrictive clause? (That)
A restrictive clause is absolutely essential to the meaning of a sentence. If you take it away then the sentence will no longer make sense to the reader.
The hairy goat’s opinion that the young monkey could not juggle chainsaws while standing on one leg was sadly proven to be correct.
The part of the sentence underlined above, “opinion that the young monkey could not juggle chainsaws while standing on one leg,” is restrictive because the sentence does not achieve anything without it:
The hairy goat’s opinion was sadly proven to be correct.
What was his opinion, who or what did he have an opinion on?
What’s a nonrestrictive clause? (Which)
A nonrestrictive clause is the part of a sentence that can be completely left out without changing the meaning of the sentence. Simply put, it’s just additional information.
The hairy goat’s opinion, which we all agreed with, was that the monkey could not juggle chainsaws while standing on one leg.
In this example, the phrase “which we all agreed with” is additional information. Its inclusion or exclusion does not really change the meaning of the sentence. If we take it out, the sentence remains plausible:
The hairy goat’s opinion was that the monkey could not juggle chainsaws while standing on one leg.
So that’s it in a nutshell. Many people will argue that the rules are not quite so straightforward but—in our opinion—simple is best, and if you can master the differences between nonrestrictive clauses and restrictive clauses you’re pretty much there.
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