signature tune (also theme tune)

usu brief tune used to introduce a particular broadcast or performer 信号曲, 开始曲（通常为短曲, 用於一广播前或演出者出场前）.

sight-read, sight-reading, sight-screen (also screen), sighted, sighting, sightless, sights, sightseeing, sightseer, sign, sign in, sign language, sign on, signal, signal-box, signaller (US signaler), signally, signalman, signatory, signature, signet, signet ring, significance, significant, significantly, signification, signify, signor, signpost, Sikh, silage, silence, silencer, silent, silent film, silently, silhouette, silica, silicate, silicon,