Correct Use of Conjunctions
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As is a conjunction. We use it before a clause, and before an expression beginning with a preposition.
- He did as he was told.
- He fought as a tiger does.
- Nobody knows her as I do.
- In 1939, as in 1914, everybody seemed to want war.
In informal English like is often used as a conjunction instead of as. This is very common in American English. It is not generally considered correct in a formal style.
- Nobody knows her like I do.
As in the sense of though
- Though he was young, he fought valiantly.
- Young as he was, he fought valiantly.
- Though the elephant was strong, it could not face the swift leopard.
- Strong as the elephant was, it could not face the swift leopard.
This structure is used to talk about purpose.
- We went early so as to get a good seat.
- He climbed up a tree so as to get a good view of the procession.
We use such as with a noun to introduce examples.
- My doctor told me to avoid fatty foods such as bacon or hamburgers.
- I have bought many fireworks such as rockets.