like and as: similarity, function
We can use like or as to say that things are similar.
We can also use as to talk about function – the jobs that people or things do.
like (similarity): like me
Like can be a preposition. We use like, not as, before a noun or pronoun to talk about similarity.
like + noun/pronoun
- My sister looks like me. (not
… as me.) - He ran like the wind. (not
… as the wind.) - Like his parents, he is a vegetarian.
We can use very, quite and other adverbs of degree before like.
- He’s very like his father.
- She looks a bit like Queen Victoria.
We can use like to give examples.
- She’s good at scientific subjects, like mathematics. (not
… as mathematics.) - In mountainous countries, like Peru, …
as (similarity): as I do
As is a conjunction. We use it before a clause, and before an expression beginning with a preposition.
as + clause
as + preposition phrase
- Nobody knows her as I do.
- We often drink tea with the meal, as they do in China.
- In 1939, as in 1914, everybody seemed to want war.
- On Friday, as on Tuesday, the meeting will be at 8.30.
like I do (informal)
In modern English, like is often used as a conjunction instead of as. This is most common in an informal style.
- Nobody loves you like I do.
Inverted word order: as did all his family
In a very formal style, as is sometimes followed by auxiliary verb + subject (note the inverted word order, (see here).
- She was a Catholic, as were most of her friends.
- He believed, as did all his family, that the king was their supreme lord.
as you know, etc
Some expressions beginning with as are used to introduce facts which are ‘common ground’ – known to both speaker/writer and listener/reader. Examples are as you know, as we agreed, as you suggested.
- As you know, next Tuesday’s meeting has been cancelled.
- I am sending you the bill for the repairs, as we agreed.
There are some passive expressions of this kind – for example as is well known; as was agreed. Note that there is no subject it after as in these expressions (see here).
- As is well known, more people get colds in wet weather. (not
As it is well known …) - I am sending you the bill, as was agreed. (not
… as it was agreed.)
Comparison with as and like after negatives
After a negative clause, a comparison with as or like usually refers only to the positive part of what comes before.
- I don’t smoke, like Megan. (Megan smokes.)
- I am not a Conservative, like Joe. (Joe is a Conservative.)
Before a negative clause, the comparison refers to the whole clause.
- Like Emily, I don’t smoke. (Emily doesn’t smoke.)
- Like James, I am not a Conservative. (James is not a Conservative.)
Function or role: He worked as a waiter.
Another use of as is to say what function or role a person or thing has – what jobs people do, what purposes things are used for, what category they belong to, etc. In this case, as is a preposition, used before a noun.
- He worked as a waiter for two years. (not
… like a waiter.) - Please don’t use that knife as a screwdriver.
- A crocodile starts life as an egg.
Compare this use of as with like.
- As your brother, I must warn you to be careful. (I am your brother.)
- Like your brother, I must warn you to be careful. (I am not your brother, but he and I have similar attitudes.)
Note that as is often pronounced /əz/ (see here).
For comparisons with as … as, (see here).
For alike, (see here).
For like used instead of as if, (see here).
For the same as, (see here).
For What … like?, (see here).
For such as, (see here).
For like used to join two infinitive structures, (see here).