SPECULATION AND DEDUCTION. MODAL VERBS, ADJECTIVES AND ADVERBS.

modal verbs: must/ may/ might/ can’t/ should

1. MUST

w Use must + infinitive to say that we are almost sure sth is true about the present.

w Use must have + past participle to say that we are almost sure sth was true o happened in the past.

MUST + INF

" present                                                    almost SURE is/ was true                                                                                  or happened in the present/ past           

MUST HAVE + PAST PARTICIPLE

" past

2. CAN’T and COULDN’T

w We can can’t and can’t/ couldn’t + perfect infinitive to say that we are almost sure that sth isn’t true in the present o didn’t happen/ wasn’t true in the past.

  

NOTE:  Not musn’t/ musn’t have.

CAN’T

                                                                   almost SURE isn’t/ wasn’t

CAN’T                  +  perfect infinitive COULDN’T               (HAVE + past participle)                                    [e.g. have been]

          true or didn’t happen in the present/ past    

            

                          

           

3. MAY, MIGHT and COULD

w We use may/ might/ could + infinitive and may/might/ could + present infinitive to say that we think it’s possible that sth is true in the present or was true/ happened in the past.

MAY          MIGHT       + infinitive COULD

   " present      

                                                 think it’s POSSIBLE true/

                                              or happened in the present/ past

MAY          MIGHT       + perfect infinitive COULD

   

 " past                           

                                    

   

4. SHOULD

w Use should + infinitive/ should have + past participle to describe a situation you expect to happen or would expect to have happened in the past. 

SHOULD + infinitive

 " present  

                                       EXPECT to happen/ 

SHOULD have + participle

" past                                 have happened in the present/ past

                                           

adjectives and adverbs for speculation

5. BOND and SURE

w Bound and sure are adjectives. We use be bound/ be sure + infinitive to say that we think sth is certain to be true or to happen.

BE  +     BOUND        +   infinitive                        SURE

                          CERTAIN

                          to be true/ happen in the future     

 

 6. LIKELY and UNLIKELY

w Likely and unlikely are adjectives. We can use subject + be likely/ unlikely + infinitive, or it is likely/ unlikely + that + clause. (= probably/ expected)

subject +    BE   +      LIKELY          + infinitive                                   UNLIKELY

  

   

7. DEFINITELY and PROBABLY

w Definitely and probably are adverbs. They go before a main verb and after the auxiliary in positive sentences; and before the auxiliary verb in negative sentences.

  

auxiliary verb   +      DEFINITELY       + main verb                               PROBABLY

 +    sentence

  

     

DEFINITELY       + auxiliary verb +  main verb PROBABLY

     –   sentence

     

  

w With be they go after the verb in positive sentences and before it in negative sentences.

BE +      DEFINITELY                                    PROBABLY

 +    sentence                                                                                                                                                                                                                                                                      

DEFINITELY    + BE                       PROBABLY

     –   sentence