As and Like

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Try an exercise about 'as' and 'like' here.

As
1: 'As' can mean 'because'.
  • As it was raining, we stayed at home.
2: 'As' can mean 'while' or 'at the same time':
  • As I was walking down the street, I saw Julie.
3: We can use 'as' to talk about the way one thing is similar to another thing. In this case too, 'as' is a conjunction and needs to be followed by a subject and a verb or by a prepositional phrase. Sometimes we invert the subject and the verb in a formal style.
  • John loves spicy food, as I do (or 'as do I', more formally).
4: We need to use 'as' with expressions like 'as much as' and by 'as adjective as'. This is also talking about similarity. These expressions can be followed by a subject and a verb or a noun or preposition.
  • John loves spicy food as much as I do.
  • Lucy travels as much as me.
  • She's as clever as her sister is.
  • London's not as big as Mexico City.
5: 'As' can be used with a noun to show someone's position. This is especially common with jobs. In a similar way, 'as' can also be used to show something's function (what we are using it for). It must be followed by a noun.
  • She works as a teacher.
  • Don't use the knife as a screwdriver.
Watch out! You can't use 'like' for someone's real job. You need to use 'as'.
  • I work like a waitress.
Like
1: 'Like' can be used to give examples. It means the same as 'for example' and is usually followed by nouns or pronouns.
  • I love big cats, like lions.
  • Western European countries like France and Spain have high unemployment at the moment.
2: We can also use 'like' to talk about how one thing is similar to another thing. Here 'like' is a preposition and is followed by a noun or a pronoun.
  • John loves spicy food, like me.
  • Tokyo is a busy and exciting city, like London.
When we're talking about how things are similar, we often use 'like' with verbs such as 'look', 'sound' and 'smell'.
  • She looks like her mother.
  • It looks like rain.
  • That sounds like a car.
  • The kitchen smells like lemons.
Traditionally, 'like' needed to be followed by a noun. However, in modern English, we often use 'like' as a conjunction and so it is followed by a subject and a verb. Some people think this is not correct, but it's very common.
  • John loves spicy food, like I do.
'Like' vs 'as' for similarity
Often, we can use both 'as' and 'like' to talk about similarity.
  • I love coffee, like Julie / I love coffee, like Julie does.
  • I love coffee, as Julie does.
We need to follow 'as' with a clause (a subject and a verb). When we use 'as' for similarity, it's not followed by a noun or pronoun.
  • I love coffee, as Julie.
However, when we use 'as' to mean a role or job (it's followed by a noun in this case), then we can't use 'like'. Instead, 'like' is talking about similarity.
  • As your mother, I'm telling you not to go out now. (I am your mother and I am telling you this in my role as your mother.)
  • Like your mother, I'm telling you not to go out now. (I'm not your mother, but I am telling you the same thing as she is. I am acting in a similar way to your mother.)
Here's another example.
  • She works as the manager (= she is the manager).
  • She works like the manager (= she isn't the manager, but she works in a similar way to the manager).
Try an exercise about 'as' and 'like' here.