  In essence, the two tagging methods (direct tagging and tagging with
sentences compression) are to tag the information we need by using regular
expression which basing on the inherent language patterns of the natural
language. Though it has many advantages in extracting regular data, Direct
tagging is not applicable to some situations. if the data we need extract is
not regular and its surrounding words are regular is relatively regular, then
we can use information compression to cut the information we do not need before
we tagging the data we need. In this way we can increase the precision of the
data while not undermine the recall of the data.
