Fill in the blanks with must, must not, can or cannot.
1You have been working all day. You ............... be tired.
Wrong!
Use "must" when the evidence makes you sure something is true.
2She does the same thing every day. She ............... be very bored with her job.
Wrong!
Use "must" because doing the same thing every day makes boredom a logical conclusion.
3It ............... be the postman. He has already been.
Wrong!
Use "can't" because the postman has already been, so this conclusion is impossible.
4You ............... be joking.
Wrong!
Use "must" in the fixed reaction "You must be joking" when something is surprising or hard to believe.
5When I saw her, she was crying. She ............... have a problem.
Wrong!
Use "must" because her crying is evidence that she has a problem.
6There is no light in his room. He ............... be asleep.
Wrong!
Use "must" because no light in the room makes sleep a logical conclusion.
7She is new to the city. She ............... have many friends here.
Wrong!
Use "can't" because being new to the city makes it unlikely that she has many friends there.
8He has been living in this city for well over two decades. He ............... know a lot of people here.
Wrong!
Use "must" because living in the city for over two decades strongly suggests he knows many people.
9You haven't eaten anything since morning. You ............... be hungry.
Wrong!
Use "must" because not eating since morning makes hunger a logical conclusion.
10You have just had lunch. You ............... be hungry now.
Wrong!
Use "can't" because having just had lunch makes hunger unlikely or impossible.
11He worked really hard for this promotion. He ............... be pleased.
Wrong!
Use "must" because working really hard for the promotion makes pleasure a logical conclusion.
12They live in the same neighborhood. They ............... know each other.
Wrong!
Use "must" because living in the same neighborhood makes it very likely that they know each other.
Done.
Score: 0/12
Answers
- You have been working all day. You must be tired.
- She does the same thing every day. She must be very bored with her job.
- It can’t be the postman. He has already been.
- You must be joking.
- When I saw her, she was crying. She must have a problem.
- There is no light in his room. He must be asleep.
- She is new to the city. She can’t have many friends here.
- He has been living in this city for well over two decades. He must know a lot of people here.
- You haven’t eaten anything since morning. You must be hungry.
- You have just had lunch. You can’t be hungry now.
- He worked really hard for this promotion. He must be pleased.
- They live in the same neighborhood. They must know each other.
