A word that can be used in three main ways:
Subordinating conjunction:
It can introduce a number of different types of ADVERBIAL CLAUSE:
 Time:
As the train drew into Victoria station, Gloria softened.
 Reason:
As they are fast-drying … the application technique is slightly different.
 Manner:
The talk that night was about experiments carried out to explain why people behaved as they did.
 Comment:
That, as I understand it, is the law.
Preposition:
Should I get a job as a barmaid?
Adverb:
It can also be used as an adverb in comparisons:
He’s as happy as a sandboy.
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