She is taller than him. (NOT She is taller as me.) (NOT She is taller that me.)

She earns more than I do. (NOT She earns more as I do.) (NOT She earns more that I do.)

As is used to say that two people or things are equal in some way. It is used in the structure as…as and the same…as.

Than and that are not used in comparisons of equality.

The baby’s eyes are the same color as yours. (NOT The baby’s eyes are the same color than yours.) (NOT The baby’s eyes are the same color that yours.)

As and than can introduce clauses in which there is no subject or object pronoun. In this case, they act like relative pronouns.

The meeting was as successful as had been expected. (NOT The meeting was as successful as it had been expected.)

You worry more than is good for you. (NOT You worry more than it is good for you.)

Don’t forget to take your ticket to the airport, as I did last year. (NOT Don’t forget to take your ticket to the airport, as I did it last year.)

• John is taller than his brother. (NOT John is taller as his brother.) (NOT John is taller that his brother.)
• She earns more than I do. (NOT She earns more as/that I do.)

As…as…

The structure as…as… is used to say that people or things are equal in some way. Than and that are not used in this way.

She is as tall as he is. (NOT She is as tall than he is .) (NOT She is as tall that he is.)

As and than clauses with missing subject or object

As and than can introduce clauses in which the subject or object is missing. Note that these structures are mainly used in a formal style.

The meeting was as successful as had been expected. (= The meeting was as successful as it had been expected.)
They gave me more than I had asked for. (NOT They gave me more than I had asked for it.)
Don’t forget to take your ticket, as I did yesterday. (NOT Don’t forget to take your ticket, as I did it yesterday.)

Background actions
All three words can be used to talk about a longer background action that was going on when something else happened.

While / as / when they were sleeping, somebody broke into the house.
As / when / while I was walking down the street, I saw a strange sight.

Note that as-, when- and while- clauses can begin a sentence. They can also be put at the end of sentences.

We normally use progressive tenses in clauses beginning with as, when or while. Simple tenses are also possible especially with verbs like sit, lie or grow.

To talk about simultaneous long actions, we usually use while. Both continuous and simple tense forms can be used.

While you were playing I was working.
John tidied the room while Jane cooked supper.

As can be used with simple tenses to talk about situations that change together.

As I get older, I get happier.

When can be used to talk about ages.

When we were children we lived in a farm house.

The expressions just as or just when are used to talk about two short actions that happen at the same time.

Just as I opened my eyes, I saw a strange sight.
Just when I stepped out, the telephone rang.

After when and while, it is possible to leave out subject + be.

Start when ready. (= Start when you are ready.)
While in Rome, do as Romans do. (= While you are in Rome, do as Romans do.)

She made me angry. (Here the adjective angry is the complement of the object me.)
You are driving us crazy. (Here the adjective crazy is the complement of the object us.)
They appointed him monitor. (Here the noun monitor is the complement of the object him.)
I found his attitude strange.
Don’t call me a liar.
They painted the wall green.
The noise drove him mad.
That case made the lawyer famous.
We find the cost of living in cities rather high.

Verb + Object + As + Complement

Note that after some verbs the object complement is introduced by as. This is common when we are describing somebody or something.

They elected John as their leader.
I regard him as a genius.

She described her attacker as a tall dark man.

Note that the structure is also possible with as being.

We do not regard him as being dangerous. OR We do not regard him as dangerous.

Verb + object + to be + complement

Verbs such as believe, consider, feel, know, find, think, prove, understand etc., can be followed by object + to be + adjective/noun phrase.

Events proved him to be wrong.
Most people supposed him to be innocent.
I considered the plan to be unwise.
I knew him to be conscientious.

Note that in an informal style, these sentences can be re-written using that-clauses.

Events proved that he was wrong.
Most people supposed that he was innocent.
I considered that the plan was unwise.
I knew that he was conscientious.

Alternate means ‘every second’ in turns.

We spend alternate weekends at our farm house.

Alternatively can mean ‘different’, ‘instead’ or ‘on the other hand’.

You can go by air, or alternatively you can hire a taxi.

As and since

Both as and since can be used to refer to the reason for something. Note that these are used when the reason is already known to the reader or the listener.

As she was not there, I left a message with her mother.

As it is raining again, we will have to cancel the match.

Since she had not studied well, she could not score good marks.

Note that as- and since- clauses usually come at the beginning of sentences.

As- and since- clauses are formal. In an informal style we use a so-clause.

She was not there, so I left a message with her mother.

It is raining again, so we will have to cancel the match.

Because clauses are used when the reason is the most important part of the sentence.

Because I was ill for six months, I lost my job.

Back and again

Back and again have similar meanings.

Back is an adverb particle. When used with a verb, it suggests a return to an earlier situation. Again cannot be used with a verb in this way.

Give me my money back. (NOT Give me my money again.)

This cake isn’t good. I am taking it back to the shop. (NOT I am taking it again to the shop.)

Again

When used with a verb, again suggests repetition.

His behavior was very disgusting. I am not going to invite him again. (NOT I am not going to invite him back.)

I am wondering why she never invites us back to her parties.

Bring and take

Bring is used for movements to the place where the speaker or the hearer is. Take is used for movements to other places.

Bring me a cup of coffee. (Here we are talking about moving a cup of coffee to the place where the speaker is.)

Bring me that file. (NOT Take me that file.)

Can you take the car to the garage?

As a conjunction since means ‘from and after the time when’.

I have never seen him since I left school.
Many things have happened since he died.
We have been living here since I was a boy.
It has been raining since we reached the city.

Note that when since is used as a conjunction denoting time it should be preceded by a verb in the present perfect, and followed by a verb in the past tense.

Since can also mean ‘seeing that’, ‘as’, ‘inasmuch as’ and similar ideas.

Since that is the case, I will excuse you. (= As that is the case, I will excuse you.)
Since it is raining, we can’t go out. (= As it is raining, we can’t go out.)

OR
The conjunction or is used to introduce an alternative.

You can have tea or coffee.
We can wait or we can go.
You may take this or that.

Or can mean otherwise.

You must study hard or you will not pass.

In some cases or can be used as an equivalent to and.

They were not wanting in strength or courage, but they were poorly motivated. (= They were not wanting in strength and courage but they were poorly motivated.)

If

If can mean ‘on the condition that’.

If he comes we will meet him.
If you ask, he will help.
If you heat ice, it melts.

If can also mean ‘admitting that’.

If I am blunt, I am at least honest. (Admitting that I am blunt, I am at least honest.)

If can mean ‘whether’.

I asked him if he would come.
I don’t know if she is interested in the offer.

If is also used to express wish or surprise.

If only I knew!

That

As a conjunction that is used to express a reason or cause.

He was annoyed that he was contradicted. (= He was annoyed because he was contradicted.)
She was upset that he didn’t write to her. (= She was upset because he didn’t write to her.)

That can express a purpose.

We eat that we may live.
We sow that we may reap.

That is also used to express consequence, result or effect.

He was so angry that he tore the letter up.
She was so weak that she sat down to rest.
It was so late that we didn’t go out.

Than

As a conjunction, than is used with comparative adjectives and adverbs.

She is taller than her husband.
Wisdom is better than riches.
I love you more than he does.

While

While means ‘during the time that which’.

While you were playing I was working.
While there is life, there is hope.
The boys sang while the girls danced.

While can also mean ‘whereas’.
While he is hard working, his brother is quite lazy.

By using though and although

Note that both though and although mean the same.

Although/ though he is ill, he is cheerful.
Although/though he works hard, he doesn’t earn much.
Poor though he is, he will not pocket this insult. (=Though he is poor, he will not pocket this insult.)

By using as

Strong as he was, he could not beat the enemies. (=Though he was strong, he could not beat the enemies.)

By using however

However difficult the problem may be, we are determined to solve it.

By using whatever

Whatever may have been his intentions, he invited us cordially.
Whatever you say, I shall not lose my temper.

By using the phrase all the same

He is poor; all the same he is happy with his lot.

By using even if

Even if he is guilty, you have no right to beat him like that.

By using an absolute participle, followed by a noun clause

Admitting that she is well-meaning, is it practical to act on her advice?

By using the phrase ‘at the same time’

He is hard up; at the same time he is generous.

By using the phrase ‘none the less’ or ‘nevertheless’

He is well-meaning; nevertheless he is unpopular.
He is rich; none the less he is miserable.

By using indeed followed by but

He was ruined indeed, but he didn’t lose heart.

Note that the same idea may be expressed in a number of ways. Study the following examples carefully.

Though he was strong he could not beat the enemies.
Strong as he was he could not beat the enemies.
However strong he may be, he could not beat the enemies.
He is strong; all the same he could not beat the enemies.
He is strong; nevertheless he could not beat the enemies.

Use bring when something is being moved towards the speaker.

Bring me a glass of water. (Here the water is being moved towards the speaker.)

Use take when something is being moved away from the area of the speaker.

I must take this paper with me. (Here the paper remains with me but it is being moved away from my area because I am also moving.)
I will take my brother with me when I go abroad. (Both my brother and I are moving away from my area.)
Bring that file to me at my desk. (Here the file is being moved towards I, the speaker.)
Should I take her a cup of tea in the bed?

Like and as

Like is either a verb or a preposition. It cannot be used as a conjunction. As is a conjunction.

She talks and walks like her mother does. (Wrong – Here ‘like’ is used as a conjunction.)
She talks and walks as her mother does. (Right)
She talks and walks like her mother. (Right – Here ‘like’ is used as a preposition.)

Note that a preposition is always followed by a noun. A conjunction is followed by a noun and verb.

Without and unless

Without is a preposition. It is followed by a noun or noun equivalent. Unless is a conjunction. It is followed by a clause (noun + verb).

Compare:

We cannot play without his permission. (Here the preposition without is followed by the noun ‘his permission’.)
We cannot play unless he gives us permission. (Here the conjunction unless is followed by the clause ‘he gives us permission’.)

Exercise

Correct the following sentences.

1.    I like these kind of apples.
2.    Do you like this sort of meat pies?
3.    These kinds of car is very fast.
4.    I won’t believe this sorts of lies.
5.    She lay the book on the chest of drawers.
6.    He likes to lay in the sun for several hours.

Answers

1.    I like these kinds of apples.
2.    Do you like this sort of meat pie?
3.    This kind of car is very fast.
4.    I won’t believe these sorts of lies.
5.    She laid the book on the chest of drawers.
6.    He likes to lie in the sun for several hours.