used in comparisons to refer to the extent or degree of something.
eg: hailstones as big as tennis balls
used to indicate that something happens during the time when something is taking place.
eg: Frank watched him as he ambled through the crowd.
同义词：while、just as、even as、(just) when、at the time that、at the moment that
used to indicate by comparison the way that something happens or is done.
eg: dress as you would if you were having guests in the (same) way that the (same) way like.
同义词: in the (same) way that、the (same) way、like
eg: I must stop now as I have to go out.
同义词: because、since、seeing that/as、in view of the fact that、owing to the fact that、on account of、for
相当于 even though
eg: sweet as he is, he doesn’t pay his bills.
同义词: though、although、even though、in spite of the fact that、despite the fact that、notwithstanding that、for all that、albeit、however
used to refer to the function or character that someone or something has.
eg: he got a job as a cook.
同义词: like、in the guise of、so as to appear to be、in the role of、being、acting as
during the time of being (the thing specified).
eg: he had often been sick as a child