---How much salt did you put in the soup? ---I’m sorry to say, _____. I forgot.
He had _____ me to come to the party, but he didn’t show up.
E-mail, as well as telephones, _____ an important part in daily communication.
The water will be further polluted unless some measures______.
---Excuse me, sir, is this seat taken? ---_______.
--- Do you think Bob will attend the meeting this afternoon? --- ______.