Speculate speculate = to guess about the possible causes or effects of something without knowing all the facts or details
present Speculating about the present
must must + infinitive It’s 2 pm. Peter hasn’t eaten since 6 am. What can we deduce? HUNGRY must feel He must feel hungry. mustsure is We use must because we are sure something is true.
maymightcould may / might / could + infinitive Mary is absent today. What can we deduce? ILL maymightcould She may / might / could be ill. maymightcould maybe is We use may / might / could because maybe it is true.
maynot may not + infinitive I’m not sure whether I can lend you any money. What can we deduce? HAVE ENOUGH may not I may not have enough. maynotmaybeis not We use may not because maybe it is not true.
can’t can’t + infinitive He has just eaten 6 hamburgers! What can we deduce? HUNGRY can’t be He can’t be hungry. can’talmost sure not true We use can’t because we are almost sure it is not true.
Why is the baby crying? hungry must She must be hungry.
Why is the baby crying? happy can’t She can’t be happy.
Why is the baby crying? spoiled maymightcould She may / might / could be spoiled.
Why is the student sleeping in class? tired must He must be tired.
Why is the student sleeping in class? the class / boring maymight could The class may / might /could be boring.
Why is the student sleeping in class? Teresa / his teacher can’t Teresa can’t be his teacher.
Why are the students so happy? Teresa / their teacher must Teresa must be their teacher.
Why are the students so happy? English class now may might could They may / might /could have English class now.
Why are the students so happy? a test today can’t They can’t have a test today.
must/may/might/could/can’t Congratulations on passing your exam. You … be very pleased. must … That woman is asking a lot of questions. She … be a journalist. Or perhaps she’s a spy. maymightcould … may / might / could …
must/may/might/could/can’t Relax and do the test. You’re an excellent student. You … fail. can’t … Where’s Bob? I don’t know. He... be having lunch. maymightcould … may / might / could … She’s very bad-tempered. She...have many friends. can’t …
must/might/could/can’t A: Do you know where my address book is? B: It...be in the hall cupboard. I think I saw it the other day. maymightcould … may / might / could … This parcel is making a ticking noise – throw it out of the window! It... be a bomb! (September 12th, 2001, in the USA) must …
past Speculating about the past
Why are 9 th grade students so happy? must have done They must have done an excellent English test. maymight could have had They may /might / could have had an English class. can’t have done They can’t have done lots of ECA on the weekend.
past Speculating about the past mustmaymightcouldcan’t must / may / might / could / can’t + HAVE + PAST PARTICIPLE
past Speculate about the past using these verbs: ENJOY LEAVE GO BE SEND Henry’s office is locked. He... home. must... must have gone... I’m not sure but this house... a school once. might... might have been... Jane is such a nice girl. She... me this rude e- mail. can’t... can’t have sent...
past Speculate about the past using these verbs: ENJOY LEAVE GO BE SEND A: Do you know where my umbrella is? B: No, but you... it at school. may... may have left... I don’t know why you wanted to stay at that party. You... talking to all those boring people. can’t... can’t have enjoyed...
past Speculate about the past using a SUITABLE verb. A: Did you hear the explosion? B: What explosion? A: There was a loud explosion a few minutes ago. You... it. must... must have heard... A: Where is Julia? B: I don’t know. She... to the toilet. may... may have gone...
past Speculate about the past using a SUITABLE verb. A: Who was the man we saw with Ann yesterday? B: I’m not sure. It... her brother. might... might have been... You got here very quickly! You... a taxi. must... must have taken... It rained every day during their holiday at the seaside, so they... a very nice time. can’t... can’t have had...
past Speculate about the past using a SUITABLE verb. I wonder why Bob didn’t phone me. He... might... might have forgotten... I left my bike outside the house last night and this morning it isn’t there anymore. Somebody... it. must... must have stolen... I saw some students at the mall, but they didn’t talk to me. They... me. can’t... can’t have seen...