Modals for speculation and deduction

Maria lives near Pico do Jaraguá.

When you’re almost sure of something now:•It must be a very quiet place.

When you believe something is a possibility now:•It may be a little boring.•It might be a little boring.•It could be a little boring.

When you’re almost sure something is impossible now:•It can’t be noisy there.

Maria used to live near Paulista Avenue.

When you’re almost sure of some situation in the past:•It must have been very noisy there.

When you believe something was a possibility in the past:•It may have been exciting to live there.•It might have been exciting to live there.•It could have been exciting to live there.

When you’re almost sure something was impossible in the past:•It can’t have been very cheap.

Should can also be used for speculation and deduction

• I sent a postcard to Germany yesterday. It should arrive in two weeks.

This is what I expect to be happening now, or to happen in the future

• Four weeks ago, I sent a postcard to Germany. It should have arrived by now.

This is what I expect to have happened in the past.

Adjectives and adverbs for speculation and deduction

When you’re almost sure

Bound to / sure to [adj.]•She is sure to know. She’s an expert on that subject.•He is bound to win the fight. He’s much stronger and more skilled than his opponent.

Definitely [adv.]•She’ll definitely pass the exam. She worked very hard.•She definitely won’t pass the exam. She didn’t do any work at all.

When it’s reasonable to expect something

Likely / unlikely [adj.]•She’s likely to be home by 10 p.m. She’s an early bird.•It’s likely that she will be home by 10 p.m.•She’s unlikely to stay out late.•It’s unlikely that she will stay out late.

Probably [adv.]•She’ll probably return home before 10 p.m.•She probably won’t stay out late.

Probably and definitely [adv.]Go before the main verb in affirmative sentences and before the auxiliary in negative sentences:•She’ll probably return home before 10 p.m.•She probably won’t stay out late.•She’ll definitely pass the exam. She worked very hard.•She definitely won’t pass the exam. She didn’t do any work at all.

However, if the main verb is to be, they go after it in affirmative sentences and before it in negative sentences:•He’s probably British.•The painting definitely isn’t genuine.