MODALS OF DEDUCTION

MODALS OF DEDUCTION

1. in Present

   • We use MUST when we feel sure that something is true because there’s very strong evidence.
     • He must live near here because he comes to work on foot. We don’t know where he lives but we’re sure it’s not far away.
   • We use might, may or could to say that we think something is possible but we’re not sure.
     • Did you hear that? I think there might be a burglar downstairs. She’s not sure there’s a burglar but she thinks it’s possible. We’ll try to get there early but we may arrive late if there’s a lot of traffic.
   • We use can’t when we feel sure something is not true.
     • It can’t be far away now. We’ve been driving for hours. Where’s the map? Really? He has to work on Christmas Day? He can’t feel very happy about that.

2. in Past

   • In the same way that we use modal verbs to say how certain we are about things in the present we can also use them to speculate about the past.
     • we use deduction the form is MODAL + have + past participle
       • Must have + past participle
         • We use ‘must have + past participle’ when we are quite sure about something.
           • You must have been very pleased when you received the results of your exams. He must have forgotten his phone at home again.
       • Might have/may have/could have + past participle
         • We use ‘might have/may have/could have + past participle’ when we are not sure about something but we think it was possible.
           • He was supposed to be here an hour ago but he could have been stuck in a traffic jam. He may have said he was coming but I can’t really remember. I wasn’t listening. I might have been here when I was a child but I can’t really remember.
       • Can’t have + past participle
         • We use ‘can’t have + past participle’ for things that we are sure did not happen in the past.
           • You can’t have seen him this morning. He was with me all the time. She can’t have liked the show. She hates musicals.

3. We use modal verbs to say how sure we are about something.

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