The exam will be on the first half of the book.That means we’ll have to finish___.
These changes may cost quite a lot, _____ they will save us money in the long run.
The couple had quarreled all time before they their engagement
I am sorry I can’t spare any paper for you, for, you see, I have _____ myself.
Obama was elected ____ first black president of the United States four years ago and has been elected _____ president again for the next four years.
Can you tell the _____ difference between the words “require” and “ request”? I sometimes get puzzled by their meanings.