本来就轮不到will
shall = must do
should = recommend to do
may = optional

will = nothing has being done

口语里面shall也是商量提议的口气
法律用语的shall才有强制的意思

Will

Will is used to show desire, preference, choice or consent:
I will accept your offer.
Will you please be quiet?

To show the future:
It will be a great party.
I will probably go out tonight.

To express capability:
The ship will take three hundred guests.
This bottle will hold two litres of wine.

To express determination or insistence:
I will pass my driving test.
I will do as you say.

Would

Would – used to show preference
I would rather go to the cinema today. (I prefer going to the cinema today.)

Would – to show a wish
I would like to have more free time.

Would – for advice
If I were you, I would study economics.

Shall

Shall – to make a suggestion
Shall we dance?
Shall I go now?

Shall for obligation in very formal situations
You shall obey the rules.
Students shall not enter here.
There shall be no food and drink on the premises.

Should

Should is often used to give an opinion, to make a suggestion, express a preference or an idea.
You should stay at home if you are feeling tired.
I should walk to work.
He should be more open to ideas.

Should – to ask for an opinion.
Should we tell him about our idea?
What should we do now?

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