grammar-o

on: normally on is used before the date, but in the English nowadays it is fine for people not to add on. e.g. I go to church Sunday.
otherwise: differently , or in another way. e.g. he think a, but she thinks otherwise. / mary , otherwise known as mr. tsui, is my girlfriend.
out of the line: 脫節
of: modifier. eg. he is a man of honour. this is a matter of great urgency.
observe：obey e.g. observe good personal hygiene
obliged to : 有責任去/被逼去
other and one another: each other and one another are the same
opposite can be an adj or a preposition. for adjective, it should have "to" . for pre, it does not. eg. the building opposite to our school is a cityscraper.
officiate:
to be in charge of or to lead a ceremony or other public event.  eg.
    A priest officiated  at  the wedding.
-or:can be pronounced as schwa, or /o/. eg. 讀schwa, dictation, diction. 讀/o/ , e.g. guarantor. 讀 schwa or /o/, mentor, corridor, condor
object complement; eg. We made him happy. / He prized the gate open./ I knocked him unconscious.
object放在句子頭係強調個object. eg. it has done him little good. 可說, Little good has it done on him.
occupied=preoccupied