You can only be sure of_________ you have at present; you cannot be sure of something _____ you might get in the future.
As we promised, we will place orders with you if the price you provided is competitive.
Since he often travels on business, he can himself to sleeping in any place he can find.
I think she is right but I am not completely sure.
The club, _ _ 25 years ago, is holding a party for past and present members.
When Peter speaks in public, he always has trouble _ the right things to say.