  Based on the results of N-body simulations on the last 2.5 Gyr evolution of
the Large and Small Magellanic Clouds (LMC and SMC, respectively) interacting
with the Galaxy, we firstly show when and where the leading arms (LAs) of the
Magellanic stream (MS) can pass through the Galactic plane after the MS
formation. We secondly show collisions between the outer Galactic HI disk and
the LAs of the MS can create giant HI holes and chimney-like structures in the
disk about 0.2 Gyr ago. We thirdly show that a large amount of metal-poor gas
is stripped from the SMC and transfered to the LMC during the tidal interaction
between the Clouds and the Galaxy about 0.2 and 1.3 Gyr ago. We thus propose
that this metal-poor gas can closely be associated with the origin of LMC's
young and intermediate-age stars and star clusters with distinctively
low-metallicities with [Fe/H] < -0.6.
