plot axis appearance problem

Hello,

When I plot any data with simple plot command in 
R, for example :-

plot(time,co2,ylim=c(350,380),xlim=c(1993,2003),xlab=NA,ylab=NA,type="p",col=5)

Then the first value of x-axis(350) and 
y-axis(1993) never starts from origin, always they 
sifted from the origin. Is there any command that 
I can correct this in the ploted figure and both 
the axis values start from origin.

Thanks for help,

Regards,
Yogesh

===========================================
Yogesh K. Tiwari,
Max-Planck Institute for Biogeochemistry,
Beutenberg Campus, Hans-Knoell-Strasse 10,
D-07745 Jena,
Germany

Office   : 0049 3641 576 376
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e-mail   : yogesh.tiwari at bgc-jena.mpg.de