>A german taxi-driver, Franz Bussman, recently found a brother who was
>thought to have been killed twenty years  _____.
>there are three choices: (a) ago (b) before (c) previously

'Ago' takes the moment of occurrence of the discourse as reference
point; so in 1999, '20 years ago' would mean 1979. 'Before' and
'previously' take as reference point whatever has been set up by
surrounding discourse. So the taxi driver may have found out in 1997
that the brother was alive, in which case the date of his presumed death
would have been 1977, if 'before' or 'previously' were used.

Incidentally, I find 'previously' ill-formed; I prefer 'previous',
although that then sounds elliptical ('previous to the date of the
taxi-driver's discovery of the truth').

Either 'ago' or 'before' work fine for me, depending on which reference
point is needed. 'Recently' suggests that 'ago' would be the more
appropriate choice. 'Recently' by default suggests 'close to now', hence
the reference point may be the present. But it is also true that what
'recently' refers to can vary depending on surrounding discourse. In
milennial terms, 1950 is 'recent' to today, but in a smaller time-frame,
say the 20th century, 1950 looks a lot less 'recent' to 1999.

Another lesson in the value of context in grammar.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Johanna Rubba   Assistant Professor, Linguistics
English Department, California Polytechnic State University
One Grand Avenue  • San Luis Obispo, CA 93407
Tel. (805)-756-2184  •  Fax: (805)-756-6374 • Dept. Phone.  756-259
• E-mail: [log in to unmask] •  Home page: http://www.calpoly.edu/~jrubba
Summer 1999: Unavailable 6/29-7/29 • Before 6/29 and after 7/29:
Response to voice- or e-mail within one week
                                       **
"Understanding is a lot like sex; it's got a practical purpose,
but that's not why people do it normally"  -            Frank  Oppenheimer
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