Choose the correct answers to complete the gaps. Use American English in all your answers -- 'must not' or 'can't.'
Mr Brown left the office ten minutes ago. It takes him about half an hour to get home. Mr Brown ...... home yet.
can't be
must not be
Jason gets paid 500 euros a month so he ...... a 1,000 euro stereo just like that.
can't buy
must not buy
The cleaning lady broke her leg last month so she ...... the 26th floor right now. You see, the elevator's broken down and we have to use the stairs these days.
can't be sweeping
must not be sweeping
Carol's not answering the doorbell which means that she ...... home now. If she were home, she'd answer it right away.
can't be
must not be
I suppose the restaurant ...... . You can tell that there are some people inside.
can't be closed
must not be closed
The shop ...... closed. The door is not locked, you see.
can't be
must not be
The butcher's ...... open yet. There seems to be no one inside and all the lights are off.
can't be
must not be
Your auntie ...... the letter yet. My brother works at the village post office and he tells me there were no letters sent this week at all.
can't have posted
must not have posted
The chef ...... very well. Every time I pass the restaurant, it's empty.
must not cook
can't cook
My grandmother's not answering the doorbell. She ...... at home. Well, she's a little dull of hearing and may not actually hear the bell.
must not be
can't be
Your son ...... maths much. He usually scores pretty poorly in exams, so I guess he's got some trouble getting the grasp of it.
must not understand
can't understand
My best friend walked past me without saying a single word yesterday. He ...... me, I guess, for if he had, he would have said something.