‘As’ and ‘like’ are two little words that can cause all manner of problems. The reason? Because very occasionally they can be used the same way, but the vast majority of the time, despite having similar meanings, grammatically they must be used quite differently.
Here are a few cases in point:
As I said before, we are not going to change the price.
Like I said before, we are not going to change the price.
= the same meaning/the same grammatical construction
As my father was before me, I am a pilot.
I’m a pilot, like my father.
= the same meaning (more or less) / but completely different grammatical constructions
He looks as if/though he hasn’t slept.
He looks like he hasn’t slept.
= the same meaning (but we must use as if/though)
I didn’t order pizza as I had also had pizza for lunch.
I really like pizza, though.
= totally different meanings
I love a lot of Tom Cruise’s movies, such as Top Gun.
I love a lot of Tom Cruise’s movies, like Top Gun.
= although people ‘say’ both of these things, like is actually incorrect here, because it means similar to, not an example of.
Now you can see where the confusion comes in.
However, with an appreciation of the different meanings of the two words (and adherence to the correct grammatical construction), it’s easy to move past any mistakes with ‘as’ and ‘like’. Here is all you need to know.
‘As’
As can be used in five distinct ways:
1) As an example of something
As a teacher, I understand the difficulties of any education system. (I am an example of a teach = I am that thing!)
We saw all of the most important sights, such as the Colosseum. (The Colosseum was an example of one of the sites we saw).
2) In reference to something
As you said, it’s a difficult thing to do. (that’s what you said)
3) To compare two things that are not the same
He looked as if/though he had seen a ghost. (something similar to that, but obviously not that exactly!)
That bag is the same as mine.
She’s not as tall as my sister.
4) At the same time
As I was leaving, she was arriving.
5) Because / the reason for something
I didn’t call as I didn’t want to wake you up.
‘Like’
Like can be used in three distinct ways:
1) To compare two things that are not the same
You look like you have seen a ghost. ((something similar to that, but obviously not that exactly!)
She is just like her sister.
2) To be in favor of something
I like pizza.
3) In reference to something
Like you said, it’s a difficult thing to do. (that’s what you said)
4) As an example of something
Try to do some exercise, like walking. (it doesn’t have to be exactly that!)
When ‘as’ and ‘like’ mean the same thing
So, here are some examples of sentences using ‘as’ and ‘like’ where the meaning is the same (although not necessarily the grammatical construction of the sentence).
As you said, it’s good fun. / Like you said, it’s good fun.
You should go somewhere interesting, such as Vietnam. / You should go somewhere interesting, like Vietnam.
He looks as if/though he’s going to fall asleep. / He looks like he going to fall asleep.
