Callan Stage 10, Lesson 146, page 823, start with: Which modal can express the idea that we're sure something is true because it makes logical sense in a particular situation?

Sentence Structures: 

• Q.Which modal can express the idea that we're sure something is true because it makes logical sense in a particular situation?
• A.The modal "must' can express the idea that we are sure something is true because it makes logical sense in a particular situation.
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• Q.Give me an example, please.
• A.Alison must have a lot of money because she owns houses in four different countries.
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• Q.Which modals can express the idea of "probably"?
• A.The modals 'should" and "ought to" can express the idea of "probably".
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• Q.Give me an example, please.
• A.They just said on TV that it ought to be nice and sunny tomorrow
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• Q.Which modals can express the idea of "perhaps"?
• A.The modals "may", "might" and "could" can express the idea of "perhaps'.
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• Q.Give me an example, please.
• A.Quick! If you run, you might catch that bus!
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• Q.Which modal expresses the idea that we're is not true because it makes no logical sense in a particular situation?
• A.The modal "can't" expresses the idea that we are sure something is not true because it makes no logical sense in a particular situation.
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• Q.Give me an example, please.
• A.Amy can't be in her flat. I've called there three times and nobody's answered.
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• Q.When we use modals in this way, what do we do when we're talking about something that happened in the past?
• A.When we use modals in this way. we put the word "have" and a past participle after the modal when we are talking about something that happened in the past.
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• Q.Give me an example, please.
• A.I can't find Kim anywhere. I think she may have gone home.
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• Q.She runs every day, so I'm sure she's fit.
• A.She runs every day, so she must be fit.
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• Q.Perhaps he knows the address of the party.
• A.He might (or may/could) know the address of the party.
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• Q.I'm certain that he isn't in his office because the lights are off.
• A.He can't be in his office because the lights are off.
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• Q.I think the cake will probably taste very good.
• A.The cake should (or ought to) taste very good.
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Grammar: 

• The modals "should" and "ought to" can express the idea of "probably". 
• For example, we can say "The train should arrive soon". This means the same as "I think the train will probably arrive soon".
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• The modals "may", "might" and 'could' can express the idea of "perhaps'. 
• For example, if somebody asks us "Do you know where Sarah is?", we can answer "She could be in her office". This is similar to saying "Perhaps she's in her office".
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• The modal "can't" expresses the idea that we are sure something is not true because it makes no logical sense in a particular situation. 
• For example, if somebody says "This is Peter's jacket", we can say "No, it can't be Peter's jacket; it's too small".
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• When we use modals in this way, we put the word "have" and a past participle after the modal when we are talking about something that happened in the past. 
• For example, "John ran 30 kilometres yesterday. He must have been very tired when he finished".