  We have obtained high-resolution HI observations of N44, one of the largest
HII complexes in the Large Magellanic Cloud. The distribution and internal
motions of the HI gas show dynamic effects of fast stellar winds and supernova
blasts. Numerous HI holes are detected, with the most prominent two
corresponding to the optically identified superbubbles Shell 1 and Shell 2. The
HI gas associated with Shell 1 shows an expansion pattern similar to that of
the ionized gas shell, but the mass and kinetic energy of the HI shell are 3--7
times those of the ionized gas shell. The total kinetic energy of the neutral
and ionized gas of Shell 1 is still more than a factor of 5 lower than expected
in a pressure-driven superbubble. It is possible that the central OB
association was formed in a molecular cloud and a visible superbubble was not
fully developed until the ambient molecular gas had been dissociated and
cleared away. This hypothesis is supported by the existence of a molecular
cloud toward N44 and the fact that the apparent dynamic age of the superbubble
Shell 1 is much shorter than the age of its OB association LH47. Accelerated HI
gas is detected at the supernova remnant 0523-679. The mass and kinetic energy
in the associated HI gas are also much higher than those in the ionized gas of
0523-679. Studies of interstellar gas dynamics using ionized gas alone are
clearly inadequate; neutral gas components must be included.
