"Ought to"
The verb "ought to" has only one form. It is always followed by the infinitive with the particle "to".
"Ought to" has the following meanings:
1. Moral duty; moral obligation; friendly advice or recommendation.
You ought to support your family.
You ought to look after your children better.
You ought to consult the doctor.
(вы должны, вам следует)
When reference is made to the past "ought to" is followed by the perfect infinitive.
2. When "ought to" is followed by the perfect infinitive it expresses criticism of a past action.
He ought to have tried to speak to her.
You ought to have done it.
(a desirable action was not carried out, а ты этого не сделал)
I'm sorry. I oughtn‘t to have said it. (а я сказал)
It may also be viewed as a reproach.
3. "Ought to" may also express friendly advice, recommendation. In this case "ought to" and "should" are synonyms. They correspond to the Russian "следует".
You ought to consult the doctor.
4. Supposition implying strong probability.
The new house ought to be very comfortable.
The use of "ought to" in this case is not very common as this meaning is normally rendered by must".
"SHALL"
When "shall" is a modal verb it always combines its modal meaning with the function of an auxiliary verb, that is, it is always used with reference to the future. It is mostly used with the second and third person and has a strong stress. In Russian it is rendered by emphatic intonation.
It may express:
1. Compulsion (принуждение) or order. You shall do it immediately.
It shall be done as you wish. He shall do as I say.
2. Threat, warning or promise. You shall be sorry for it.
If you sit here you shall catch cold.
If you pass your exam you shall have a new bicycle.
3. When used in question it expresses asking for instructions. It is used with the first and third persons.
Shall I read?
Shall he answer the telephone?
Shall I get you a chair?
"Shall" is used only with the simple infinitive.
"Should"
Historically "should" was the past form of "shall" and both the forms expressed obligation. But in present-day English they have developed different meanings and are treated as two different verbs.
"Should" followed by the indefinite infinitive is used with reference to the present of future and remains unchanged in reported speech.
"Should" has the following meanings:
Advice, recommendation.
As well as "ought" it expresses desirable, proper action, and corresponds to the Russian "следует, следовало бы".
You should be more careful.
You should take this medicine twice a day.
The continuous infinitive is also possible here.
You shouldn’t 't be sitting in the sun.
Criticism of a past action but only in combination with a perfect infinitive
You should have done it (but you didn’t).
They shouldn't have left the child alone (but they did).
"Should" and "ought" are interchangeable here.
Emotional "Should"
3. In modern English "should" is often used with emotional colouring to express indignation, surprise, disappointment and other feelings.
It is observed in:
interrogative sentences beginning with "why", "what", "how".
Why should I do it (ради чего, с какой стати)?
How should I know (почем я знаю) ?
What on earth should I... ( какого черта)?
b) interrogative and exclamatory sentences with the construction "who (whom)... but" to express unexpected actions:
Returning home last night whom should I meet but cousin Jack himself.
c) exclamatory sentences after the words expressing various feelings, that is in emotionally coloured sentences.
Just imagine that he should act so!
To think that it should come to this. - Только подумать до чего дошло дело!
in object clauses after expressions of regret, surprise:
I'm sorry that he should be so unreasonable.
in attributive clauses beginning with “why” after the noun "reason".
I don't see any reason why he shouldn’t 't be happy.
"Should" in its weakened meaning.
4. Rather often "should" weakens its meaning. It is observed in the following cases:
a) in subordinate subject clauses after impersonal principal clauses with "it".
It is necessary you should do it.
It is important you should do it.
It is desirable you should do it.
in subordinate clauses after the words expressing order, suggestion, fear.
He suggested that the meeting should beat 5.
His order was (is) that we should do it.
in subordinate clauses of real condition with reference to the future to make the condition less probable.
Should you meet him tell him about it.
Should you be in M. again we’ll be happy to see you.
It corresponds to the Russian "если случайно", "случись так, что,.. " "если все же... ", "в случае если..."
in subordinate clause of purpose after the conjunction "lest" (чтобы не, как бы не).
I remind you of it lest you should forget.
I fear lest he should be late.
"WILL"
"Will" is not a purely modal verb. It generally combines its modal meaning with the function of an auxiliary verb expressing futurity. It is mostly used with the first person though it may occur with any person. "Will" has two forms: "will" for the present and "would" for the past tense. "Will" and "would" are forms of the same verb although in a few cases their meanings differ.
The modal verb "will" expresses:
1. Will, intention, volition.
It is often rendered into Russian by "непременно", "обязательно", охотно".
Now I will speak.
I can and I will learn it.
I will write as soon as I can.
I will never agree to that.
If you will wait for me I will be very glad
2. A polite request or an offer (only in questions). Will you have a cup of tea?
Will you sit down?
Resistance when speaking about lifeless thing or a refusal to do something when
speaking about people. It occurs in negative sentences.
The door will not open. It is no use trying.
The orange will not peel.
The engine won’t start.
They won't go with us.