28. ---- Who told you my email address?
---- I don’t remember clearly. It _______ Karen.
---- It _______ Karen. She doesn’t know my email address.
| A．may have been; can’t have been | B．must have been; mustn’t have been |
| C．may have been; must have been | D．must have been; mustn’t be |
They had their electricity _______ because they didn’t pay the bill.
| A．put off | B．cut off | C．set off | D．worse off |
John is very stubborn and never shows any ______ for his parents’ feelings.
| A．concentration | B．attention |
| C．determination | D．consideration |
The important task will take Peter and me about four months to complete, so it will be a long time _____ we meet you again.
| A．after | B．when | C．since | D．before |
--- How much do I owe you for the meal?
--- _______. It’s nothing.
| A．You’re welcome | B．Forget it |
| C．With pleasure | D．That’s right |
Human beings are different from animals _______ 
they can use language as a tool to communicate.
| A．in that | B．for that | C．in which | D．for which |