  (abridged) We report here a factor of 5.7 higher total CO flux in Arp~244
(the ``Antennae'' galaxies) than that previously accepted in the literature
(thus a total molecular gas mass of 1.5x10$^{10}$ Msun), based on our fully
sampled CO(1-0) observations at the NRAO 12m telescope. Our observations show
that the molecular gas peaks predominately in the disk-disk overlap region
between the nuclei, similar to the far-infrared (FIR) and mid-infrared (MIR)
emission. The bulk of the molecular gas is forming into stars with a normal
star formation efficiency (SFE) L_{IR}/M(H_2) \approx 4.2 Lsun/Msun, same as
that of giant molecular clouds in the Galactic disk. Additional supportive
evidence is the extremely low fraction of the dense molecular gas in Arp~244,
revealed by our detections of the HCN(1-0) emission.
  We estimate the local SFE indicated by the ratio map of the radio continuum
to CO(1-0) emission. Remarkably, the local SFE stays roughly same over the bulk
of the molecular gas distribution. Only some localized regions show the highest
radio-to-CO ratios that we have identified as the sites of the most intense
starbursts with SFE >~ 20 Lsun/Msun. These starburst regions are confined
exclusively in the dusty patches seen in the HST images near the CO and FIR
peaks where presumably the violent starbursts are heavily obscured.
Nevertheless, recent large-scale star formation is going on throughout the
system, yet the measured level is more suggestive of a moderate starburst (SFE
>~ 10 Lsun/Msun) or a weak to normal star formation (SFE ~ 4 Lsun/Msun). The
overall starburst from the bulk of the molecular gas is yet to be initiated as
most of the gas further condenses into kpc scale in the final coalescence.
