THURSDAY, 19th MARCH 2020: SOCIAL SCIENCE AND ENGLISH

SOCIAL SCIENCE

Page 82: activity 1

ENGLISH:

Modal verbs of speculation and deduction

must

We use must + infinitive for obligation and strong recommendation, but also to say that we are quite sure that something is true.

• They are almost identical. They must be sisters.
• But I answered all the questions correctly. There must be a mistake. 

We use must be + –ing with dynamic verbs to say that we are quite sure that something is happening now.

• What you are saying is not possible. You must be kidding.  
• Can you hear the shouting? Our neighbours must be arguing again. 

We use must have + past participle or must have been + -ing to say that we are quite sure that something was true or happened in the past.

• I can’t find my wallet! I must have dropped it in the taxi.
• You must have had a real scare when you saw the crocodile. 
• He was the only victim. He must have been sleeping when the fire started.

can’t

We can use can’t + infinitive to say that we are quite sure that something is NOT true.

• He can’t be that famous. I’ve never heard his name before. 
• She can’t be married. I have never seen a ring on her finger. 

We use can’t be + –ing to say that we are quite sure that something is NOT happening now.

• They can’t be travelling by bus. There is no bus service on Sundays. 

We use can’t/couldn’t have + past participle  or can’t have been + -ing to say that we are quite sure that something did NOT happen or was NOT true in the past.

• You can’t/couldn’t have seen John last night. He was in hospital. 
• She can’t/couldn’t have passed the test. She didn’t even open the books. 

Note that for negative deduction we use can’t and NOT mustn’t

• He can’t be that famous. (NOT He mustn’t be that famous.)

could/might/may

We can use could/might/may + infinitive to say that it’s possible that something is true (but we are not sure).

• I can’t get hold of him on the phone. He could/might/may be away. 
• We didn’t do anything when we could and now it could/might/may be too late.

We use could/might/may be + –ing to say that we are quite it’s possible that something is happening now (but we are not sure).

• Tom isn’t at the office. He might/may be working from home today.  
• ‘Why isn’t she picking up her phone.’ ‘She might/may be driving.’

We can use could/might/may have + past participle or might/may have been + -ing to say that it’s possible that something was true or happened in the past.

• It’s been three days. They could/might/may have finished painting the house by now. 
• If they left at 9, they could/might/may have already arrived.
• She was home last night, but didn’t answer the door. She might/may have been having a shower.

We can use could have + past participle to say that something was possible in the past but did not happen.

• He could have played in the first division, but he had a terrible injury.
• He could have had better jobs if he had spoken English.   

Note that we use might not or may not (NOT could not) to talk about a negative possibility.

• He seems too calm. He might/may not be aware of the risks. 
• She might/may not have heard us. Knock again. 

should/ought to

We use should/ought to + infinitive to talk about a situation that we expect to happen (present or future).

• He should/ought to be home by now. He is always home before 7. 
• They should/ought to arrive before midnight.

We use should have/ought to have + past participle to talk about a situation expected to happen in the past. We can also use this form to express criticism.

• He should/ought to have received the parcel yesterday. I sent it two days ago. 
• He should/ought to have studied more. Nobody fails if they study. 

Juego may and might para practicar