  We investigate various dynamic processes including magnetic reconnection,
chromospheric evaporation, and coronal rain draining in two limb solar flares
through imaging and spectroscopic observations from the Interface Region
Imaging Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) on board
the Solar Dynamics Observatory. In the early phase of the flares, a bright and
dense loop-top structure with a cusp-like shape can be seen in multi-wavelength
images, which is co-spatial with the hard X-ray 25--50 keV emission. In
particular, intermittent magnetic reconnection downflows are detected in the
time-space maps of AIA 304 {\AA}. The reconnection downflows are manifested as
redshifts on one half of the loops and blueshifts on the other half in the IRIS
Si {\sc iv} 1393.76 {\AA} line due to a projection effect. The Si {\sc iv}
profiles exhibit complex features (say, multi-peak) with a relatively larger
width at the loop-top region. During the impulsive phase, chromospheric
evaporation is observed in both AIA images and the IRIS Fe {\sc xxi} 1354.08
{\AA} line. Upward motions can be seen from AIA 131 {\AA} images. The Fe {\sc
xxi} line is significantly enhanced and shows a good Gaussian shape. In the
gradual phase, warm rains are observed as downward moving plasmas in AIA 304
{\AA} images. Both the Si {\sc iv} and Fe {\sc xxi} lines show a relatively
symmetric shape with a larger width around the loop top. These results provide
observational evidence for various dynamic processes involved in and are
crucial to understand the energy release process of solar flares.
