  Recurrent nova CI Aquilae is still bright 300 days after the optical maximum,
showing the slowest evolution among recurrent novae. We predict the turn-off
time of CI Aql 2000 outburst coming in August 2001 after a supersoft X-ray
source (SSS) phase lasts 250 days. We also predict helium enrichment of ejecta,
He/H = 0.25 by number. Observational confirmations are urgently required. Based
on the optically thick wind mass-loss theory of the thermonuclear runaway
model, we have also estimated the WD mass to be 1.2 +- 0.05 Msun by fitting our
theoretical light curves with the 1917 and 2000 outbursts. The mass of the
hydrogen-rich envelope on the WD is also estimated to be 6 x 10^{-6} Msun at
the optical maximum, indicating an average mass accretion rate of 0.7 x 10^{-7}
Msun/yr during the quiescent phase between the 1917 and 2000 outbursts. Using
these obtained values, we have consistently reproduced the light curve in
quiescence as well as the two outburst phases. Thus, we predict the turn-off
time to be in August 2001 for the 2000 outburst. We strongly recommend soft
X-ray observations to detect SSS until August 2001 because the massive wind
phase have already ended in December 2000 followed by an SSS phase that very
likely lasts until August 2001.
