Of
Of is commonly used to show possession or to show what something is made of (but it has a lot more usages).
Of is a preposition.
Examples
To show possession:
A part of me
The hand of God
To state what something is made of:
A heart of gold
A splinter of wood
Swedish
om, från, av, för, m.fl.
Off
Off is the opposite of on.
Off is a preposition or an adverb.
Examples
Turn it off.
Wipe that paint off the wall.
Thanks for the lift, you can drop me off just here.
Swedish
av, från, på, ur, helt, bort, m.fl.
QUIZ