Recently,　Mao　[Automatica　J.　IFAC,　49　(2013),　pp.　3677-3681]　initiated　the　study　the　mean-square　exponential　stabilization　of　continuous-time　hybrid　stochastic　differential　equations　by　feedback　controls　based　on　discrete-time　state　observations.　In　the　same　paper　Mao　also　obtains　an　upper　bound　on　the　duration　tau　between　two　consecutive　state　observations.　However,　it　is　due　to　the　general　technique　used　there　that　the　bound　on　tau　is　not　very　sharp.　In　this　paper,　we　will　be　able　to　establish　a　better　bound　on　tau　making　use　of　Lyapunov　functionals.　We　will　discuss　the　stabilization　not　only　in　the　sense　of　exponential　stability　(as　Mao　does　in　[Automatica　J.　IFAC,　49　(2013),　pp.　3677-3681])　but　also　in　other　sense-that　of　H-infinity　stability　or　asymptotic　stability.　We　will　consider　not　only　the　mean　square　stability　but　also　the　almost　sure　stability.