That & Which

Hey, guys.

This is Alex.

Thanks for clicking, and welcome to this lesson on "that" and "which."

Now, "that" and "which" we use often in relative clauses.

So if you look at earlier on the website, we have a lesson on relative clauses that

gives a general overview.

This lesson will give you a little bit more detail on how to use "that" and "which" when

you're writing relative clauses.

So just as a bit of a review, on the board I have four sentences, and we're going to

give you a little bit more detail in this lesson about when to use "that" and when to

use "which."

And is there a difference between the two?

So for example, the first sentence that I have here is, "The movie that we saw last

weekend was really good."

Now the relative clause here is, "that we saw last weekend."

Again, a relative clause is an adjective clause, so what it does is it gives more information

about a subject.

So the subject in this sentence is "the movie."

Okay.

So with the movie being the subject, we're giving more information, okay, which movie,

the movie that we saw last weekend, and we're saying that it was really good.

So this is an identifying clause.

We call this an identifying clause because it specifically identifies the subject.

So we cannot just say, "The movie was really good."

Which movie?

If you need extra information or essential information that will add to the meaning of

the sentence, this is called an identifying clause because we are identifying which movie

we're talking about, okay?

So "The movie that we saw last weekend was really good."

Same thing with the second sentence.

So the second sentence, "The table which I bought from Ikea was cheap."

First of all, identify the subject.

What is the subject in this sentence?

All right, "the table."

Now what is the relative clause here?

What is the adjective clause?

Well, what about the table?

Give me more information about the table here.

"The table which I bought from Ikea was cheap."

So maybe you bought multiple tables, and you want to specify that, "Well, the one that

I got from Ikea was cheap," okay?

So these are both examples of identifying clauses.

Now, as you can see, we use "that" and "which" for both of them.

So when you create a relative clause or an adjective clause, the same thing, different

names, you can use "that" and "which" to give more information about things.

So they can begin a clause which has, again, this is a subordinating conjunction plus a

subject-verb-object structure, and you will get an identifying clause because you're giving

more information that's essential to the understanding of the sentence.

In these next two sentences, what you'll notice, first of all, is that we're not using

"that," okay?

So first, we have a comma here, and we have a comma here, and next sentence, we have a

comma here, and we have a comma here.

So if you watched the previous lesson, you will know that these two sentences, for example,

"Harry Potter," which I finished last week, was an excellent book, and "Toronto," which

is heavily populated, is a multicultural city, these are non-identifying clauses.

So let's write that on the board.

And now let's underline the non-identifying clauses.

We're going to talk about why these are non-identifying clauses.

Okay, so imagine this sentence here, "Harry Potter," which I finished last week, was an

excellent book.

Do you lose any meaning if you keep the sentence, "Harry Potter was an excellent book"?

Not really.

So what this does, what a non-identifying clause is, is something that gives you more

information, extra information about a subject.

So your subject here is "Harry Potter."

Your subject here, "Toronto," which is heavily populated, is a multicultural city.

You have a subject.

And you don't really lose any meaning if you take out the non-identifying clause.

So "Harry Potter was an excellent book."

You still understand my meaning exactly.

"Toronto" is a multicultural city.

You understand my meaning.

What I'm doing here in the non-identifying clause is giving extra information, non-essential,

not necessary information, but it is information that can give you a little bit of a richer

meaning to a sentence, okay?

Now, the key thing when you're using "that" and "which" is, first of all, we use them

to give more information about things, okay?

So computers, movies, tables, desks, books, anything you can think of.

Now, where they differ, you can use both, first of all, when you're doing an identifying

clause, "that" and "which."

So for example, I could also say, "The movie which we saw last weekend was really good.

I can also say, "The table that I bought from Ikea was cheap."

But here, if you're doing a non-identifying clause, if you're writing one, you can only

use "which" inside the non-identifying clause.

You cannot say, "Harry Potter, that I finished last week, was an excellent book."

You cannot say, "Toronto, that is heavily populated, is a multicultural city."

You must use "which."

Okay, so if you'd like to test your understanding of "that," "which," identifying and non-identifying

clauses and test out your writing skills, check out the quiz under this video on www.engvid.com.

Good luck, guys, and take care.