sure 是很爽块地回答可以,一定,无疑的.of course 是理所当然的意思.两者很多情况下能混用.举例,必须用sure的时候:He is clever, to be sure, but not very hard-working. She is sure to pass the examination.必须用 of course的时候:Mothers as a matter of course have much affection for their children.I will write to you of course, but not every week.