I have studied my science test Thursday afternoon.A. at; on B. on; for C. for; on
The ice isn’t ______________ to skate on.
---Are you going to ____________ your friends to your party? ---Yes, sure.
---Must I clean the floor now? ---__________. It is too dirty.
---How long may I _____________ the book? ---Two weeks.
These aren’t my keys. Mine ___________ in the drawer.