So far we've looked at various kinds of words and how those words can be modified in different ways to create subtle variations in meaning. This is all very well and good, but sometimes you'll find yourself wanting to express some meaning that is too complicated for a single word to express, and that's when you'll want to use clauses.
Let's run through an example: "The bicycle rolled down the hill" is a perfectly reasonable sentence. But let's say that we wanted to give more information about this bicycle. If we wanted to mention that the bicycle is blue then we can just use the adjective "blue"; "The blue bicycle rolled down the hill". But let's say we wanted to say something more complicated, such as the fact that I just bought this bicycle yesterday. One option might be to use two separate sentences to express this concept; "The bicycle rolled down the hill. I just bought it yesterday.". The problem with this is that it is long and cumbersome. What would be great is if we could somehow take that second sentence and jam it into the first sentence right next to the word "bicycle" just like we did with "blue". Something like "The 'I-just-bought-this-bicycle-yesterday' bicycle rolled down the hill".
A relative clause will allow us to do exactly that.
A relative clause is a sentence that that is pretending to be an adjective in the sense that it is describing a noun. For this reason they are sometimes also called adjectival clauses. We create a relative clause in English by taking a complete sentence and removing the noun that we are describing and adding the special word "that" to the beginning of the sentence. When we jam a relative clause into another sentence in English we have to put it after the noun that it's describing.
In our example above, we wanted to take the sentence "I just bought it yesterday" and turn it into a relative clause. The noun that we're describing is the bicycle which is here represented by the pronoun "it". If we follow the steps we end up with the clause "that I just bought yesterday". So our full and complete sentence should look something like this:
- The bicycle that I just bought yesterday rolled down the hill.
Perfect. That's exactly what we wanted.
By the way, be very careful with the word "that" in English. "That" has quite a lot of uses and just because you see this word doesn't mean you have a relative clause on your hands. In fact the word "that" isn't even always needed when you're making relative clauses; we could just as easily said this:
- The bicycle I just bought yesterday rolled down the hill.
Here's a few more examples of sentences that contain relative clauses.
- The ball that I see is red.
- The man wearing the suit walked away.
- The cup that is upside-down has a spider underneath it.
- I finally got the book that I've always wanted.
Japanese and Korean, both being verb-final languages, place their relative clause before the noun that it is modifying.
- 제가 읽고 싶은 책을 샀습니다.
- I bought the book that I want to read.
- Literally: that-I-want-to-read book, bought.
Nominal clauses take the place of nouns.
- I know that the ball is red
Adverbial clauses act like adverbs.
Clauses of time
Clauses of time determine when something happened.
- I was reading when she entered.
Clauses of Reason
Adverbial clauses that justify the meaning of the clause they determine are called clauses of reason.
She left because she was in a hurry.
You won't go, since you can't.
Clauses of Purpose
Adverbial clauses that show the purpose, the objective of the subject of the verb they determine.
She left early, (so as/in order) to catch the bus.