We use of course to mean something like as everybody knows or as is obvious. It looks as if the sun goes round the earth, but of course the earth really goes around the sun. Of course is not a polite reply to a statement of fact. Compare: ‘Could you help me?’ ‘Of course.’ ‘It …
Of course means ‘without any doubt’ or ‘certainly’. ‘Can you help you?’ ‘Of course.’ ‘Can I join your group?’ ‘Yes, of course.’ ‘Could you get me something to drink?’ ‘Of course.’ ‘Do you know what I mean?’ ‘Of course.’ Of course is also used for giving permission in a polite way. ‘May I come in?’ …
