DearMsJiang，
Iwasunabletocometo1stand2ndperiodtoday.Duetotherainyesterday,Iwaswetandhadtemperatureatnight.Thedoctoradvicedmetorestforseveraldaysandaftermyrecovery,Iwillattendschoolassoonaspossible.Iamsincerelysorryabouttheinconvenience.However,Iwouldliketohaveyourpermission.Also,afterwardsIwouldphoneyouandthere'sthecertificatebythedoctor.Li.
Yours
XXX