SIGMETS and AIRMETS seem to be misunderstood by many applicants.  Private, Instrument, and Commercial applicants should expect to be asked about both and with a little review these are pretty easy.  SIGMETS consist of Convective SIGMETS and “the others”.   AIRMETS consist of three types, Tango, Sierra, and Zulu.  A great summary is on the Aviation Weather Center (AWC) web site.