Welcome to Oxford Online English!

In this lesson, you can learn about sentence structure in English.

You'll learn how to construct all kinds of sentences in English, from the simplest

possible sentences, to long, complex sentences which contain many different ideas.

To begin, a question:

What's the simplest sentence you can make in English?

What does every sentence in English need?

Every sentence needs a verb.

The simplest sentence is an imperative, which means when you tell someone to do something.

For example:

Run!

Leave!

Work!

These are the simplest complete sentences you can make in English; they're just one

word long!

Of course, most sentences are longer than this.

Most sentences that are longer than one word also need a noun before the verb.

This noun is the subject.

With a subject plus a verb, you can make simple sentences like:

He runs.

She left.

They're working.

You can see that the verb can be in different forms: past or present, simple or continuous.

The verb form doesn't change the structure of the sentence.

These are all the same: subject plus verb.

Of course, these sentences aren't very interesting.

You can't say much with short sentences like these.

Let's add a little more information.

Take the sentence he runs.

What could you add after runs to make it longer?

You could add an adverb of place:

He runs around the park.

You could add an adverb of time:

He runs every morning.

You could add both:

He runs around the park every morning.

You could add an adverb of manner:

He runs slowly.

You can see that you have many choices, but your choices are also limited.

In this case, you can use different kinds of adverbs, but there are also things you

can't use.

For example, you can't use another verb after run, you can't use an adjective, and

you can't use a noun, or at least you can't use a noun with this meaning of run.

This is an important point, so let's look at it in more detail.

To build grammatically complete sentences in English, there's one important question:

what needs to come next?

For example, you saw the sentence he runs.

That's a complete sentence.

You can put a full stop after runs, and it's correct.

It's very basic, but it's correct.

What about these:

She likes He wants

We go

These aren't complete sentences.

Can you explain why not?

They aren't complete, very simply, because they aren't finished.

Look at the first sentence: She likes.

She likes…what?

She has to like something.

He wants…

What does he want?

You can't just 'want', you have to want something.

We go…

Where?

At this point, we want to teach you a word: complement.

The complement is the thing you add after a verb to make a sentence complete.

A complement can have many different forms.

It can be a noun, a verb, an adjective or an adverb.

These things can be single words or phrases.

For example, when we say 'noun', we also mean noun phrases.

So, table is a noun, and the wooden table which my grandmother gave me is also a noun.

Both nouns refer to one object—one table.

For this lesson, a noun can be one word, or a phrase.

Okay, let's practice.

Look at the first sentence: she likes.

How could you finish this?

What are the possible complements?

Pause the video and write down three endings for your sentence.

Try to use different ideas and structures.

Ready?

Let's look at some possible answers.

These are just our suggestions; of course there are many possibilities!

She likes strawberries.

She likes swimming.

She likes getting up before the sun rises.

She likes to listen to music while she works.

You can see that there's more than one possible complement: you can use a noun, a gerund (a

verb with -ing which acts like a noun), a gerund phrase, or an infinitive verb with

'to'.

So, you have many choices!

However, like before, your choices are also limited.

Only certain structures are possible.

The idea of complements isn't just for the first verb in the sentence.

Many words need a complement.

For example, look at one of the sentences you just saw:

She likes getting up before the sun rises.

Technically, you can say She likes getting up.

It's a grammatically complete sentence, but you'd never say it.

Why not?

Because it doesn't make any sense.

You need more information.

She likes getting up… when?

Why?

How?

You need a complement after getting up to complete the idea.

She likes getting up before…

Before also needs a complement.

You can't stop there.

Before what?

She likes getting up before the sun….

This also doesn't work, because it doesn't make sense.

It doesn't make sense because the sun needs a complement.

Before the sun does what?

She likes getting up before the sun rises.

Ok, finally we have a sentence which is both grammatically complete and which communicates

meaning.

What should you remember from this?

Remember that when you use a particular word, you have limited choices in what kind of word

you use next.

To speak or write in clear, correct English, you don't just need to know English words.

You need to know what can come next.

For example, with a verb like like or want, it's not enough to know the verb.

You also need to know whether the verb needs a complement, and what complements are—or

aren't—possible.

This is why it's good to learn vocabulary in full phrases and sentences.

That way, you'll know how to use the words you learn to make sentences you can use in

your spoken or written English.

Using what you've seen up to now, you can build many simple English sentences.

Let's see how you can add more information and more detail to these simple sentences.

You can add information to a simple sentence in two ways: you can add adjectives or adverbs.

Let's look at an example, using a sentence we started before, but we didn't finish:

He wants…

Actually, you should do some work!

Pause the video, and finish this sentence in three different ways.

Start again when you have your answers.

Ready?

Here's our suggestion:

He wants to buy a car.

Now, let's add some description using adjectives and adverbs.

Can you see how you could add adjectives to this sentence?

You could add adjectives before the word car, like this:

He wants to buy a new car.

He wants to buy a second-hand car.

He wants to buy a bright red car.

What about adverbs?

Could you add adverbs to these sentences to add some details?

There are many possibilities; for example:

Apparently, he wants to buy a new car.

He wants to buy a second-hand car next month.

He wants to buy a bright red car for his new girlfriend.

You can see that adverbs can be single words or phrases.

Adjectives can go before the noun they describe, or after some verbs.

Adverbs are more complicated, and can go in many different positions.

However, this is the important point: using adjectives and adverbs like this doesn't

change whether a sentence is complete or not.

If you say:

He wants to buy a car.

That's a complete sentence.

You can add adjectives and adverbs to it to make it more detailed:

Apparently, he wants to buy a second-hand car for his new girlfriend.

However, if a sentence is incomplete, then you can't make it complete by adding adjectives

or adverbs:

He wants to buy…

This sentence is incomplete.

Adding adjectives and adverbs won't make it complete.

So, at this point, you can build a simple sentence.

You also hopefully understand something about complements and why they're important for

making complete sentences, and now you can also add description to a complete sentence

using adjectives and adverbs.

Let's see how you can combine these simple sentences into complex ones.

First, let's define some words.

A conjunction is something which joins two sentences or two parts of a sentence together.

Words like and, but, if, although, because or which are conjunctions.

A complex sentence contains two or more parts joined with a conjunction.

These parts are called clauses.

An independent clause expresses a complete idea, and could stand by itself.

A dependent clause would not make sense if it were by itself.

A dependent clause depends on an independent clause in the same sentence in order to have

meaning.

Don't worry if this is new—you don't need to remember everything right now.

You'll see lots of examples of these ideas in this section and the next section, too.

In this section, you're going to learn about complex sentences with two independent clauses.

Okay, enough abstract talk!

Let's see some examples:

He runs around the park every morning, so he's in pretty good shape.

She likes strawberries, but she hardly ever eats them.

You should write to her and thank her for the present.

These are simple examples of complex sentences.

Here's your recipe: independent clause + conjunction + independent clause.

You generally need a comma at the end of the first clause, before the conjunction, but

comma rules are quite flexible in English, so you won't always need a comma.

Look at the first example:

He runs around the park every morning, so he's in pretty good shape.

Which word is the conjunction?

The conjunction is so.

You can split this sentence into two full, meaningful sentences:

Let's look at one more:

She likes strawberries, but she hardly ever eats them.

Again, you can split this into two full sentences.

You might think that the second sentence

here isn't complete or doesn't make sense by itself.

As it is, you'd be right.

However, you can change them to strawberries, and then it's a complete, meaningful sentence:

But, she hardly ever eats strawberries.

You can keep adding conjunctions and clauses for as long as you want:

She likes strawberries, but she hardly ever eats them, and she doesn't earn much money,

so she has to be careful how much she spends on groceries, and fresh food is generally

more expensive than canned or frozen produce, so…

Of course, just because you can, it doesn't mean it's a good idea.

Sentences with too many clauses are difficult to follow, so it's generally better to limit

your complex sentences to two or, maximum, three clauses.

Now, you know how to build complex sentences using independent clauses.

What about dependent clauses?

Do you remember the definition of a dependent clause?

A dependent clause is a part of a sentence which would not make sense by itself.

Let's see an example:

She's taller than I am.

This short sentence has two clauses.

Can you see where the two clauses start and end, and which one is dependent?

The two clauses are:

She's taller.

And: Than I am.

They're linked with the conjunction than.

The second clause, than I am, is dependent.

It doesn't make sense by itself.

Let's see some other ways to build complex sentences with dependent clauses.

You can add a dependent clause with conjunctions like if, because, although, unless, or wherever.

For example:

If you're late, I'll leave without you.

He's broke because he spent all his money on beer.

Although she spends a lot of time at work, she doesn't get much done.

I won't do it unless you come with me.

We can meet wherever you want.

Often, you can change the order of the two clauses if you want, so you can say: