'as' and 'like'

I worked as an actor for two years.
I went home early as I felt ill. 
He looks as if he hasn't slept.
As you know, this is the third time I've had to complain.
He looks like his dad. 
She's like a sister to me.
Try to do something relaxing, like reading a book or having a bath.

Grammar explanation

as and like are often confused since they can both be used for comparisons. There are, however, important differences.

Making comparisons

as + adjective + as and as much as

We often use the structure as + adjective + as or as much as to say if something has, or doesn't have, the same amount of that quality as something else. 

She loves curry as much as I do.
He's not as tall as his brother.
It's not as expensive as the other hotel.
That dog is as big as that child!

You also have to use as in the expression the same as.

Your phone is the same as mine.
Texting is not the same as speaking in person.

like + noun

In the following comparisons, like is followed by a noun or a pronoun to say that two things are similar.

He's like a father to me.
She's acting like a child.
It's like a burger but with big mushrooms instead of bread.
There are lots of people like us.

It is also common to make comparisons using like with verbs of the senses.

She looks like her mother.
It sounds like a cat.
Nothing tastes like homemade lemonade.
It smells like medicine.
It feels like cotton.

as if/as though + clause

As if and as though can be used to compare a real situation to an imaginary situation. They are followed by a clause (a subject and verb).

You look as if you've seen a ghost.
I felt as if I was floating above the ground.
You talk as though we're never going to see each other again.

Giving examples

We can say like or such as to give examples. 

You could try a team sport like football, basketball or hockey.
You should take something soft, such as a towel, to lie on.

Talking about a job or function

We can use as + noun to talk about a job or function. 

I worked as a shop assistant for two years.
He used his coat as a blanket to keep warm.

as to connect two phrases

as can be used as a conjunction to connect two phrases. It can have different meanings.

as = 'because'

All the tickets were sold out as we got there too late.
As the road was closed, I had to park on the next street.

as = 'while' or 'during the time that'

She called as I was getting out of the bath.
As they were arriving, we were leaving.

as = 'in the way that'

As we expected, it started to rain.
As you know, classes restart on 15 January.
As I said, I think this project will be a challenge.

** Note that in informal speech, people sometimes say like for 'in the way that'.

Like I said, I didn't know her.

 

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