  Studies of the CO and HI radio emission of some evolved stars are presented
using data collected by the IRAM Plateau de Bure interferometer and Pico Veleta
telescope, the Nan\c{c}ay Radio Telescope and the JVLA and ALMA arrays.
Approximate axial symmetry of the physical and kinematic properties of the
circumstellar envelope (CSE) are observed in CO emission, in particular, from
RS Cnc, EP Aqr and the Red Rectangle. A common feature is the presence of a
bipolar outflow causing an enhanced wind velocity in the polar directions. HI
emission extends to larger radial distances than probed by CO emission and
displays features related to the interaction between the stellar outflow and
interstellar matter. With its unprecedented sensitivity, FAST will open a new
window on such studies. Its potential in this domain is briefly illustrated.
