DearAnne,
Thankyouforyourinvitationtodinneratyourhometomorrowevening.Unfortunately,itismuchtomyregretthatIcannotjoinyouandyourfamily,becauseIwillbefullyoccupiedthenforanimportantexamcomingthedayaftertomorrow.Ifeelterriblysorryformissingthechanceofsuchahappyget-together,andIhopethatallofyouenjoyagoodtime.Isitpossibleforyouandmetohaveaprivatemeetingafterward?Ifso,pleasedon'thesitatetodropmealineaboutyourpreferabledate.Idolongforapleasantchatwithyou.
Pleaseallowmetosaysorryagain.
Regards,
LiMing