For starters try to better understand what is actually a deduction or deduction. The dictionary gives us the following definition of the word: the process of using the knowledge or information you have in order to understand something or form an opinion. In other words, it is — a conclusion to which we arrive at by applying the general law to a particular case. Want a vivid example? Please:
Noting general details such as the position of the cups, pens, knives, Sherlock came to the conclusion — the victim was left-handed.
In English, we have a whole group of modal verbs that help us express how likely we think this or that assumption. Starting from very unlikely to very likely the chain will look like this:
can not — might — could — may — must
These verbs can be used for the present, past and future. After all these verbs used the infinitive without the particle to. But first things first.
For actions in the present. Present actions
- If we are 100% sure that this or that assumption is not true, we use can not.
He can not be right-handed. He writes with his left hand, I saw it. — It can not be right-handed. He writes with his left hand, I saw it.
Important note: the affirmative form of the verb can can be used only for the general assumptions, such as:
It can be very cold here in winter. — It can be very cold in winter. (t. e. it happens from time to time)
- Might, may, could used if you have certain evidence in favor of a suggestion, but you doubt.
He might get a lot of important phone calls during the day. I saw an open notepad by the phone. — Maybe he often call on important issues. I saw the open notebook by the phone. (but it does not mean anything, maybe he phoned someone was in the evening)
He could be a busy man. I can see a lot of notes in his notepad. — Maybe he busy man. I’ve seen a lot of records in his notebook. (but it is also always at home, maybe I’m wrong, so just guessing, but do not say 100%)
He may love coffee. I saw a half-finished cup on the table. — Maybe he likes coffee. I saw a half-full cup of drink. (but he could cook it for a guest)
- If you are absolutely sure of something, feel free to eat must.
He must have a dog. I saw dog food. — He should have a dog. I saw the food.
- If you make a suggestion about something that is happening at the moment, after the modal glagola should be used be + Verb + ing.
They must be having a party, the music is very loud. — He must have them now party, playing music very loudly.
He can not be working today, it is Christmas! — It can not be that it worked today. Christmas back!
They may be skiing right now. They went to the mountain yesterday. — They probably go skiing today.
For actions in the past. Past actions
- Still, most of the guesswork Sherlock concerning the events that have already occurred. How on the basis of assumptions to show that we are talking about last time? When you need to use a modal verb have + Past participle. Below are examples of Past Modals of Deduction.
He can not have committed the suicide. He was left-handed, the wound is on the right side of his head. — He could not commit suicide. The wound on the right side, and he was left-handed.
He may have made himself a sandwich. There is some bread and butter left on the table. — Maybe he made himself a sandwich. On the table were bread and butter.
He must have been in the middle of a phone conversation, when someone came because he did not hang up the receiver. — I guess he was just talking on the phone when someone came, because he has not hung up.
- This assumption might look like this:
He must have been talking on the phone, when someone came. — He must have talked on the phone when someone came.
If we want to emphasize that the proposed action lasted in the past for some time after the modal verb is used have + been + Verb + ing.
Important note: If we just described the situation without making any assumptions in this context should be consumed Past Continuous:
He was talking on the phone when someone came. — He was on the phone when someone came.
For actions in the future. Future actions
Modal verbs may, might, could be used to express uncertainty about the future. In this case, after they used the infinitive without the particle or to be + Verb + ing.
I might (may) be working on Saturday. — Maybe I’ll work on Saturday.
We could meet for lunch tomorrow. — We could have lunch together tomorrow.
Other ways to express possibility and certainty
Also modals of deduction in the English language, there are other ways to express possibility and certainty (probability and certainty).
1. What exactly is going to happen
- To be bound to do something — something to happen of course, necessary.
Our team is much more prepared. We are bound to win. — Our team is more than prepared. We will win.
- Something will definitely happen — something is bound to happen.
Peter will definitely get this job — Peter certainly get the job done.
- To be sure to do something — definitely do something.
Margaret is sure to fail the test. She has not done anything. — Margaret exact test failure. She did not do anything.
2. Something maybe / probably happen
- To be likely to do something — there is a chance that something will happen.
Young people from rural areas are likely to move to cities. — It is likely that young people from rural areas are moving to the city.
- To be probable that — probably that.
It is probable that it will snow tomorrow. — Probably tomorrow will be snow.
- To be possible that — maybe that.
It is possible that they just lost your package. — Maybe they just lost your parcel.
3. What is likely to happen
- To be unlikely — something unlikely.
Their party is unlikely to win the elections. — It is unlikely that their party wins the election.
- To be impossible that / to do smth — it is impossible that something will happen.
It is impossible to install this program on your computer. — You can not install the program on your computer.
- Probably / definitely will not — probably / definitely not.
He definitely will not forget about your invitation. — He just forget about your invitation.
There may be some variation of the words most definitely (exactly), highly unlikely / likely (very unlikely), quite probable (quite possible), etc.
And now we offer you to work together with Sherlock. Look at the video and select the correct answer in the proposals. The transcript to the video attached. But do not look directly into the transcript. Try listening to understand what is at stake.

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