Onepossibleversion:DearTomThankyouverymuchforinvitingmetoyourbirthdayparty.I,dlovetogobutIcant.Myparentsareoutonbusiness.Theywillcomebacknextmonth.AndnowIhavetolookaftermygrandmabecausesheisillinbed.IalsoneedtostudyformycomingEnglishexam.I’mverysorrybutIcan’tgotoyourparty.Thankyouforinvitingme.Ihopeyouwillhaveagoodtime.YoursLiMing